21172108 has 12 divisors (see below), whose sum is σ = 37104760. Its totient is φ = 10570752.

The previous prime is 21172097. The next prime is 21172133. The reversal of 21172108 is 80127112.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 366 + ... + 6517.

Almost surely, 2^21172108 is an apocalyptic number.

It is an amenable number.

21172108 is a deficient number, since it is larger than the sum of its proper divisors (15932652).

21172108 is a wasteful number, since it uses less digits than its factorization.

21172108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7656 (or 7654 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 21172108 is about 4601.3158987403. The cubic root of 21172108 is about 276.6440709922.

It can be divided in two parts, 2117 and 2108, that added together give a square (4225 = 65²).

The spelling of 21172108 in words is "twenty-one million, one hundred seventy-two thousand, one hundred eight".