21790812 has 24 divisors (see below), whose sum is σ = 51606016. Its totient is φ = 7154928.

The previous prime is 21790801. The next prime is 21790841. The reversal of 21790812 is 21809712.

It is a self number, because there is not a number n which added to its sum of digits gives 21790812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12748 + ... + 14355.

Almost surely, 2^21790812 is an apocalyptic number.

It is an amenable number.

21790812 is an abundant number, since it is smaller than the sum of its proper divisors (29815204).

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

21790812 is a wasteful number, since it uses less digits than its factorization.

21790812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27177 (or 27175 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21790812 is about 4668.0629815803. The cubic root of 21790812 is about 279.3129926095.

The spelling of 21790812 in words is "twenty-one million, seven hundred ninety thousand, eight hundred twelve".