21653912 has 16 divisors (see below), whose sum is σ = 46401360. Its totient is φ = 9280224.

The previous prime is 21653909. The next prime is 21653927. The reversal of 21653912 is 21935612.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 193283 + ... + 193394.

It is an arithmetic number, because the mean of its divisors is an integer number (2900085).

Almost surely, 2^21653912 is an apocalyptic number.

It is an amenable number.

21653912 is an abundant number, since it is smaller than the sum of its proper divisors (24747448).

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

21653912 is a wasteful number, since it uses less digits than its factorization.

21653912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386690 (or 386686 counting only the distinct ones).

The product of its digits is 3240, while the sum is 29.

The square root of 21653912 is about 4653.3764085876. The cubic root of 21653912 is about 278.7268387521.

The spelling of 21653912 in words is "twenty-one million, six hundred fifty-three thousand, nine hundred twelve".