21179912 has 16 divisors (see below), whose sum is σ = 42767340. Its totient is φ = 9775296.

The previous prime is 21179911. The next prime is 21179959. The reversal of 21179912 is 21997112.

It can be written as a sum of positive squares in 2 ways, for example, as 21104836 + 75076 = 4594^2 + 274^2 .

It is not an unprimeable number, because it can be changed into a prime (21179911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101723 + ... + 101930.

Almost surely, 2^21179912 is an apocalyptic number.

It is an amenable number.

21179912 is an abundant number, since it is smaller than the sum of its proper divisors (21587428).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21179912 is a wasteful number, since it uses less digits than its factorization.

21179912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203672 (or 203668 counting only the distinct ones).

The product of its digits is 2268, while the sum is 32.

The square root of 21179912 is about 4602.1638388914. The cubic root of 21179912 is about 276.6780569817.

The spelling of 21179912 in words is "twenty-one million, one hundred seventy-nine thousand, nine hundred twelve".