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20971840 = 26565537
BaseRepresentation
bin101000000000…
…0000101000000
31110110110221211
41100000011000
520332044330
62025255504
7343154251
oct120000500
943413854
1020971840
11109244aa
127034594
134463896
142adcb28
151c93d2a
hex1400140

20971840 has 28 divisors (see below), whose sum is σ = 49939956. Its totient is φ = 8388608.

The previous prime is 20971807. The next prime is 20971889. The reversal of 20971840 is 4817902.

It can be written as a sum of positive squares in 2 ways, for example, as 16711744 + 4260096 = 4088^2 + 2064^2 .

It is a zygodrome in base 4.

It is a congruent number.

It is an unprimeable number.

In principle, a polygon with 20971840 sides can be constructed with ruler and compass.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32449 + ... + 33088.

Almost surely, 220971840 is an apocalyptic number.

20971840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20971840 is an abundant number, since it is smaller than the sum of its proper divisors (28968116).

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

20971840 is an equidigital number, since it uses as much as digits as its factorization.

20971840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65554 (or 65544 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 20971840 is about 4579.5021563484. The cubic root of 20971840 is about 275.7690429437.

The spelling of 20971840 in words is "twenty million, nine hundred seventy-one thousand, eight hundred forty".

Divisors: 1 2 4 5 8 10 16 20 32 40 64 80 160 320 65537 131074 262148 327685 524296 655370 1048592 1310740 2097184 2621480 4194368 5242960 10485920 20971840