21956016 has 40 divisors (see below), whose sum is σ = 58679280. Its totient is φ = 7065856.

The previous prime is 21956009. The next prime is 21956017. The reversal of 21956016 is 61065912.

It is not an unprimeable number, because it can be changed into a prime (21956017) 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, 6495 + ... + 9278.

It is an arithmetic number, because the mean of its divisors is an integer number (1466982).

Almost surely, 2^21956016 is an apocalyptic number.

It is an amenable number.

21956016 is an abundant number, since it is smaller than the sum of its proper divisors (36723264).

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

21956016 is a wasteful number, since it uses less digits than its factorization.

21956016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15813 (or 15807 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 21956016 is about 4685.7247038212. The cubic root of 21956016 is about 280.0170737888.

The spelling of 21956016 in words is "twenty-one million, nine hundred fifty-six thousand, sixteen".