21309492 has 24 divisors (see below), whose sum is σ = 50001952. Its totient is φ = 7063200.

The previous prime is 21309487. The next prime is 21309511. The reversal of 21309492 is 29490312.

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, 2734 + ... + 7077.

Almost surely, 2^21309492 is an apocalyptic number.

It is an amenable number.

21309492 is an abundant number, since it is smaller than the sum of its proper divisors (28692460).

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

21309492 is a wasteful number, since it uses less digits than its factorization.

21309492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9999 (or 9997 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 21309492 is about 4616.2205319937. The cubic root of 21309492 is about 277.2411546209.

The spelling of 21309492 in words is "twenty-one million, three hundred nine thousand, four hundred ninety-two".