21397264 has 20 divisors (see below), whose sum is σ = 47379904. Its totient is φ = 9170208.

The previous prime is 21397253. The next prime is 21397279. The reversal of 21397264 is 46279312.

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, 95412 + ... + 95635.

Almost surely, 2^21397264 is an apocalyptic number.

It is an amenable number.

21397264 is an abundant number, since it is smaller than the sum of its proper divisors (25982640).

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

21397264 is a wasteful number, since it uses less digits than its factorization.

21397264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191062 (or 191056 counting only the distinct ones).

The product of its digits is 18144, while the sum is 34.

The square root of 21397264 is about 4625.7176740480. The cubic root of 21397264 is about 277.6212775093.

The spelling of 21397264 in words is "twenty-one million, three hundred ninety-seven thousand, two hundred sixty-four".