21508449208 has 64 divisors (see below), whose sum is σ = 41629165920. Its totient is φ = 10414118400.

The previous prime is 21508449173. The next prime is 21508449239. The reversal of 21508449208 is 80294480512.

It is a super-2 number, since 2×21508449208² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9032178 + ... + 9034558.

Almost surely, 2^21508449208 is an apocalyptic number.

It is an amenable number.

21508449208 is a deficient number, since it is larger than the sum of its proper divisors (20120716712).

21508449208 is a wasteful number, since it uses less digits than its factorization.

21508449208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2728 (or 2724 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 43.

The spelling of 21508449208 in words is "twenty-one billion, five hundred eight million, four hundred forty-nine thousand, two hundred eight".