21372717 has 8 divisors (see below), whose sum is σ = 29267296. Its totient is φ = 13863312.

The previous prime is 21372713. The next prime is 21372719. The reversal of 21372717 is 71727312.

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

It is not a de Polignac number, because 21372717 - 2² = 21372713 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21372713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96163 + ... + 96384.

It is an arithmetic number, because the mean of its divisors is an integer number (3658412).

Almost surely, 2^21372717 is an apocalyptic number.

It is an amenable number.

21372717 is a deficient number, since it is larger than the sum of its proper divisors (7894579).

21372717 is a wasteful number, since it uses less digits than its factorization.

21372717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192587.

The product of its digits is 4116, while the sum is 30.

The square root of 21372717 is about 4623.0635946307. The cubic root of 21372717 is about 277.5150742562.

It can be divided in two parts, 2137271 and 7, that added together give a triangular number (2137278 = T₂₀₆₇).

The spelling of 21372717 in words is "twenty-one million, three hundred seventy-two thousand, seven hundred seventeen".