21117612 has 24 divisors (see below), whose sum is σ = 49530096. Its totient is φ = 7002688.

The previous prime is 21117563. The next prime is 21117631. The reversal of 21117612 is 21671112.

It is a happy number.

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 7 ways as a sum of consecutive naturals, for example, 2103 + ... + 6830.

It is an arithmetic number, because the mean of its divisors is an integer number (2063754).

Almost surely, 2^21117612 is an apocalyptic number.

It is an amenable number.

21117612 is an abundant number, since it is smaller than the sum of its proper divisors (28412484).

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

21117612 is a wasteful number, since it uses less digits than its factorization.

21117612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9137 (or 9135 counting only the distinct ones).

The product of its digits is 168, while the sum is 21.

The square root of 21117612 is about 4595.3902989844. The cubic root of 21117612 is about 276.4065108212.

Adding to 21117612 its reverse (21671112), we get a palindrome (42788724).

The spelling of 21117612 in words is "twenty-one million, one hundred seventeen thousand, six hundred twelve".