21913956 has 24 divisors (see below), whose sum is σ = 56814240. Its totient is φ = 7304616.

The previous prime is 21913951. The next prime is 21913979. The reversal of 21913956 is 65931912.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21913956.

It is not an unprimeable number, because it can be changed into a prime (21913951) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 101346 + ... + 101561.

It is an arithmetic number, because the mean of its divisors is an integer number (2367260).

Almost surely, 2^21913956 is an apocalyptic number.

It is an amenable number.

21913956 is an abundant number, since it is smaller than the sum of its proper divisors (34900284).

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

21913956 is a wasteful number, since it uses less digits than its factorization.

21913956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202920 (or 202912 counting only the distinct ones).

The product of its digits is 14580, while the sum is 36.

The square root of 21913956 is about 4681.2344525777. The cubic root of 21913956 is about 279.8381547678.

The spelling of 21913956 in words is "twenty-one million, nine hundred thirteen thousand, nine hundred fifty-six".