21957936 has 160 divisors (see below), whose sum is σ = 76328448. Its totient is φ = 5253120.

The previous prime is 21957917. The next prime is 21957961. The reversal of 21957936 is 63975912.

It is a Harshad number since it is a multiple of its sum of digits (42).

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 31 ways as a sum of consecutive naturals, for example, 47820 + ... + 48276.

Almost surely, 2^21957936 is an apocalyptic number.

21957936 is a gapful number since it is divisible by the number (26) 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 21957936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38164224).

21957936 is an abundant number, since it is smaller than the sum of its proper divisors (54370512).

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

21957936 is a wasteful number, since it uses less digits than its factorization.

21957936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499 (or 493 counting only the distinct ones).

The product of its digits is 102060, while the sum is 42.

The square root of 21957936 is about 4685.9295769356. The cubic root of 21957936 is about 280.0252358207.

The spelling of 21957936 in words is "twenty-one million, nine hundred fifty-seven thousand, nine hundred thirty-six".