21215608 has 16 divisors (see below), whose sum is σ = 40284000. Its totient is φ = 10473216.

The previous prime is 21215599. The next prime is 21215611. The reversal of 21215608 is 80651212.

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 in 3 ways as a sum of consecutive naturals, for example, 16153 + ... + 17416.

It is an arithmetic number, because the mean of its divisors is an integer number (2517750).

Almost surely, 2^21215608 is an apocalyptic number.

It is an amenable number.

21215608 is a deficient number, since it is larger than the sum of its proper divisors (19068392).

21215608 is a wasteful number, since it uses less digits than its factorization.

21215608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33654 (or 33650 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 21215608 is about 4606.0403819333. The cubic root of 21215608 is about 276.8334047582.

The spelling of 21215608 in words is "twenty-one million, two hundred fifteen thousand, six hundred eight".