21696964 has 27 divisors (see below), whose sum is σ = 40631143. Its totient is φ = 10135808.

The previous prime is 21696953. The next prime is 21696967. The reversal of 21696964 is 46969612.

It is a happy number.

The square root of 21696964 is 4658.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 3034564 + 18662400 = 1742^2 + 4320^2 .

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21696964.

It is not an unprimeable number, because it can be changed into a prime (21696967) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 158304 + ... + 158440.

Almost surely, 2^21696964 is an apocalyptic number.

21696964 is the 4658-th square number.

It is an amenable number.

21696964 is a deficient number, since it is larger than the sum of its proper divisors (18934179).

21696964 is a wasteful number, since it uses less digits than its factorization.

21696964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312 (or 156 counting only the distinct ones).

The product of its digits is 139968, while the sum is 43.

The cubic root of 21696964 is about 278.9114367138.

The spelling of 21696964 in words is "twenty-one million, six hundred ninety-six thousand, nine hundred sixty-four".