21512908 has 6 divisors (see below), whose sum is σ = 37647596. Its totient is φ = 10756452.

The previous prime is 21512893. The next prime is 21512917. The reversal of 21512908 is 80921512.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2689110 + ... + 2689117.

Almost surely, 2^21512908 is an apocalyptic number.

It is an amenable number.

21512908 is a deficient number, since it is larger than the sum of its proper divisors (16134688).

21512908 is a wasteful number, since it uses less digits than its factorization.

21512908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5378231 (or 5378229 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 21512908 is about 4638.2009443318. The cubic root of 21512908 is about 278.1205246597.

The spelling of 21512908 in words is "twenty-one million, five hundred twelve thousand, nine hundred eight".