21697304 has 16 divisors (see below), whose sum is σ = 43075800. Its totient is φ = 10210432.

The previous prime is 21697301. The next prime is 21697339. The reversal of 21697304 is 40379612.

21697304 = 1157² + 1158² + ... + 1172².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21697301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79634 + ... + 79905.

Almost surely, 2^21697304 is an apocalyptic number.

It is an amenable number.

21697304 is a deficient number, since it is larger than the sum of its proper divisors (21378496).

21697304 is a wasteful number, since it uses less digits than its factorization.

21697304 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159562 (or 159558 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 32.

The square root of 21697304 is about 4658.0364962074. The cubic root of 21697304 is about 278.9128935904.

The spelling of 21697304 in words is "twenty-one million, six hundred ninety-seven thousand, three hundred four".