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22440 = 23351117
BaseRepresentation
bin101011110101000
31010210010
411132220
51204230
6251520
7122265
oct53650
933703
1022440
1115950
1210ba0
13a2a2
14826c
1569b0
hex57a8

22440 has 64 divisors (see below), whose sum is σ = 77760. Its totient is φ = 5120.

The previous prime is 22433. The next prime is 22441. The reversal of 22440 is 4422.

Adding to 22440 its reverse (4422), we get a palindrome (26862).

It can be divided in two parts, 2 and 2440, that added together give a palindrome (2442).

22440 = 282 + 292 + ... + 442.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

22440 is an undulating number in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1312 + ... + 1328.

It is an arithmetic number, because the mean of its divisors is an integer number (1215).

222440 is an apocalyptic number.

22440 is a gapful number since it is divisible by the number (20) 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 22440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38880).

22440 is an abundant number, since it is smaller than the sum of its proper divisors (55320).

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

22440 is a wasteful number, since it uses less digits than its factorization.

22440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42 (or 38 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 12.

The square root of 22440 is about 149.7998664886. The cubic root of 22440 is about 28.2059642332.

The spelling of 22440 in words is "twenty-two thousand, four hundred forty", and thus it is an iban number.

Divisors: 1 2 3 4 5 6 8 10 11 12 15 17 20 22 24 30 33 34 40 44 51 55 60 66 68 85 88 102 110 120 132 136 165 170 187 204 220 255 264 330 340 374 408 440 510 561 660 680 748 935 1020 1122 1320 1496 1870 2040 2244 2805 3740 4488 5610 7480 11220 22440