21612406 has 8 divisors (see below), whose sum is σ = 34325640. Its totient is φ = 10170528.

The previous prime is 21612397. The next prime is 21612413. The reversal of 21612406 is 60421612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 317796 + ... + 317863.

It is an arithmetic number, because the mean of its divisors is an integer number (4290705).

Almost surely, 2^21612406 is an apocalyptic number.

21612406 is a deficient number, since it is larger than the sum of its proper divisors (12713234).

21612406 is a wasteful number, since it uses less digits than its factorization.

21612406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 635678.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21612406 is about 4648.9144969552. The cubic root of 21612406 is about 278.5486379151.

The spelling of 21612406 in words is "twenty-one million, six hundred twelve thousand, four hundred six".