21366608 has 10 divisors (see below), whose sum is σ = 41397834. Its totient is φ = 10683296.

The previous prime is 21366593. The next prime is 21366619. The reversal of 21366608 is 80666312.

It can be written as a sum of positive squares in only one way, i.e., 17073424 + 4293184 = 4132^2 + 2072^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 667691 + ... + 667722.

Almost surely, 2^21366608 is an apocalyptic number.

It is an amenable number.

21366608 is a deficient number, since it is larger than the sum of its proper divisors (20031226).

21366608 is a wasteful number, since it uses less digits than its factorization.

21366608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1335421 (or 1335415 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 21366608 is about 4622.4028383515. The cubic root of 21366608 is about 277.4886308683.

The spelling of 21366608 in words is "twenty-one million, three hundred sixty-six thousand, six hundred eight".