21901715 has 8 divisors (see below), whose sum is σ = 28671408. Its totient is φ = 15928480.

The previous prime is 21901709. The next prime is 21901739. The reversal of 21901715 is 51710912.

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

It is not a de Polignac number, because 21901715 - 2¹⁰ = 21900691 is a prime.

It is a Duffinian 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, 199052 + ... + 199161.

It is an arithmetic number, because the mean of its divisors is an integer number (3583926).

Almost surely, 2^21901715 is an apocalyptic number.

21901715 is a deficient number, since it is larger than the sum of its proper divisors (6769693).

21901715 is a wasteful number, since it uses less digits than its factorization.

21901715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398229.

The product of its (nonzero) digits is 630, while the sum is 26.

The square root of 21901715 is about 4679.9268156671. The cubic root of 21901715 is about 279.7860397766.

The spelling of 21901715 in words is "twenty-one million, nine hundred one thousand, seven hundred fifteen".