21906364 has 6 divisors (see below), whose sum is σ = 38336144. Its totient is φ = 10953180.

The previous prime is 21906359. The next prime is 21906377. The reversal of 21906364 is 46360912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2738292 + ... + 2738299.

Almost surely, 2^21906364 is an apocalyptic number.

It is an amenable number.

21906364 is a deficient number, since it is larger than the sum of its proper divisors (16429780).

21906364 is a wasteful number, since it uses less digits than its factorization.

21906364 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5476595 (or 5476593 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 21906364 is about 4680.4234851133. The cubic root of 21906364 is about 279.8058347755.

The spelling of 21906364 in words is "twenty-one million, nine hundred six thousand, three hundred sixty-four".