21618712 has 32 divisors (see below), whose sum is σ = 42547680. Its totient is φ = 10278400.

The previous prime is 21618703. The next prime is 21618739. The reversal of 21618712 is 21781612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53712 + ... + 54112.

It is an arithmetic number, because the mean of its divisors is an integer number (1329615).

Almost surely, 2^21618712 is an apocalyptic number.

It is an amenable number.

21618712 is a deficient number, since it is larger than the sum of its proper divisors (20928968).

21618712 is a wasteful number, since it uses less digits than its factorization.

21618712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 723 (or 719 counting only the distinct ones).

The product of its digits is 1344, while the sum is 28.

The square root of 21618712 is about 4649.5926703315. The cubic root of 21618712 is about 278.5757266298.

The spelling of 21618712 in words is "twenty-one million, six hundred eighteen thousand, seven hundred twelve".