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18811728 = 2432132773
BaseRepresentation
bin100011111000…
…0101101010000
31022101201211200
41013300231100
514303433403
61511111200
7315616455
oct107605520
938351750
1018811728
11a689591
126372500
133b88600
1426d982c
1519b8ca3
hex11f0b50

18811728 has 90 divisors (see below), whose sum is σ = 57081726. Its totient is φ = 5780736.

The previous prime is 18811711. The next prime is 18811757. The reversal of 18811728 is 82711881.

It can be written as a sum of positive squares in 3 ways, for example, as 1272384 + 17539344 = 1128^2 + 4188^2 .

It is a super-2 number, since 2×188117282 = 707762220691968, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18811692 and 18811701.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 23950 + ... + 24722.

Almost surely, 218811728 is an apocalyptic number.

18811728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18811728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28540863).

18811728 is an abundant number, since it is smaller than the sum of its proper divisors (38269998).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18811728 is a wasteful number, since it uses less digits than its factorization.

18811728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 813 (or 791 counting only the distinct ones).

The product of its digits is 7168, while the sum is 36.

The square root of 18811728 is about 4337.2488976308. The cubic root of 18811728 is about 265.9558597871.

The spelling of 18811728 in words is "eighteen million, eight hundred eleven thousand, seven hundred twenty-eight".

Divisors: 1 2 3 4 6 8 9 12 13 16 18 24 26 36 39 48 52 72 78 104 117 144 156 169 208 234 312 338 468 507 624 676 773 936 1014 1352 1521 1546 1872 2028 2319 2704 3042 3092 4056 4638 6084 6184 6957 8112 9276 10049 12168 12368 13914 18552 20098 24336 27828 30147 37104 40196 55656 60294 80392 90441 111312 120588 130637 160784 180882 241176 261274 361764 391911 482352 522548 723528 783822 1045096 1175733 1447056 1567644 2090192 2351466 3135288 4702932 6270576 9405864 18811728