21697312 has 48 divisors (see below), whose sum is σ = 52581312. Its totient is φ = 8582400.

The previous prime is 21697301. The next prime is 21697339. The reversal of 21697312 is 21379612.

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, 814 + ... + 6637.

It is an arithmetic number, because the mean of its divisors is an integer number (1095444).

Almost surely, 2^21697312 is an apocalyptic number.

It is an amenable number.

21697312 is an abundant number, since it is smaller than the sum of its proper divisors (30884000).

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

21697312 is a wasteful number, since it uses less digits than its factorization.

21697312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7481 (or 7473 counting only the distinct ones).

The product of its digits is 4536, while the sum is 31.

The square root of 21697312 is about 4658.0373549382. The cubic root of 21697312 is about 278.9129278696.

The spelling of 21697312 in words is "twenty-one million, six hundred ninety-seven thousand, three hundred twelve".