21642912 has 36 divisors (see below), whose sum is σ = 61547850. Its totient is φ = 7214208.

The previous prime is 21642899. The next prime is 21642923. The reversal of 21642912 is 21924612.

21642912 is a `hidden beast` number, since 2 + 1 + 642 + 9 + 12 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21566736 + 76176 = 4644^2 + 276^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a nude number because it is divisible by every one of its digits.

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 5 ways as a sum of consecutive naturals, for example, 37287 + ... + 37862.

Almost surely, 2^21642912 is an apocalyptic number.

It is an amenable number.

21642912 is an abundant number, since it is smaller than the sum of its proper divisors (39904938).

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

21642912 is a wasteful number, since it uses less digits than its factorization.

21642912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75165 (or 75154 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 21642912 is about 4652.1943209630. The cubic root of 21642912 is about 278.6796338168.

The spelling of 21642912 in words is "twenty-one million, six hundred forty-two thousand, nine hundred twelve".