21097312 has 24 divisors (see below), whose sum is σ = 41731200. Its totient is φ = 10498944.

The previous prime is 21097291. The next prime is 21097331. The reversal of 21097312 is 21379012.

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, 5889 + ... + 8767.

It is an arithmetic number, because the mean of its divisors is an integer number (1738800).

Almost surely, 2^21097312 is an apocalyptic number.

It is an amenable number.

21097312 is a deficient number, since it is larger than the sum of its proper divisors (20633888).

21097312 is a wasteful number, since it uses less digits than its factorization.

21097312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3118 (or 3110 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 21097312 is about 4593.1810327920. The cubic root of 21097312 is about 276.3179141392.

The spelling of 21097312 in words is "twenty-one million, ninety-seven thousand, three hundred twelve".