21372618 has 8 divisors (see below), whose sum is σ = 42745248. Its totient is φ = 7124204.

The previous prime is 21372577. The next prime is 21372629. The reversal of 21372618 is 81627312.

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

21372618 is an admirable number.

It is a Curzon 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, 1781046 + ... + 1781057.

It is an arithmetic number, because the mean of its divisors is an integer number (5343156).

Almost surely, 2^21372618 is an apocalyptic number.

21372618 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21372618 is a wasteful number, since it uses less digits than its factorization.

21372618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3562108.

The product of its digits is 4032, while the sum is 30.

The square root of 21372618 is about 4623.0528874327. The cubic root of 21372618 is about 277.5146457654.

The spelling of 21372618 in words is "twenty-one million, three hundred seventy-two thousand, six hundred eighteen".