21109992 has 16 divisors (see below), whose sum is σ = 52775040. Its totient is φ = 7036656.

The previous prime is 21109987. The next prime is 21110027. The reversal of 21109992 is 29990112.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 439768 + ... + 439815.

It is an arithmetic number, because the mean of its divisors is an integer number (3298440).

Almost surely, 2^21109992 is an apocalyptic number.

It is an amenable number.

21109992 is an abundant number, since it is smaller than the sum of its proper divisors (31665048).

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

21109992 is a wasteful number, since it uses less digits than its factorization.

21109992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 879592 (or 879588 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 33.

The square root of 21109992 is about 4594.5611324696. The cubic root of 21109992 is about 276.3732609917.

The spelling of 21109992 in words is "twenty-one million, one hundred nine thousand, nine hundred ninety-two".