21792816 has 30 divisors (see below), whose sum is σ = 60990020. Its totient is φ = 7264224.

The previous prime is 21792803. The next prime is 21792851. The reversal of 21792816 is 61829712.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

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

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 75526 + ... + 75813.

Almost surely, 2^21792816 is an apocalyptic number.

It is an amenable number.

21792816 is an abundant number, since it is smaller than the sum of its proper divisors (39197204).

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

21792816 is a wasteful number, since it uses less digits than its factorization.

21792816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151353 (or 151344 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 21792816 is about 4668.2776267056. The cubic root of 21792816 is about 279.3215547209.

The spelling of 21792816 in words is "twenty-one million, seven hundred ninety-two thousand, eight hundred sixteen".