21913859 has 8 divisors (see below), whose sum is σ = 25164480. Its totient is φ = 18873000.

The previous prime is 21913849. The next prime is 21913861. The reversal of 21913859 is 95831912.

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

It is a cyclic number.

It is not a de Polignac number, because 21913859 - 2²⁰ = 20865283 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21913819) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52217 + ... + 52634.

It is an arithmetic number, because the mean of its divisors is an integer number (3145560).

Almost surely, 2^21913859 is an apocalyptic number.

21913859 is a deficient number, since it is larger than the sum of its proper divisors (3250621).

21913859 is a wasteful number, since it uses less digits than its factorization.

21913859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104881.

The product of its digits is 19440, while the sum is 38.

The square root of 21913859 is about 4681.2240920511. The cubic root of 21913859 is about 279.8377418750.

The spelling of 21913859 in words is "twenty-one million, nine hundred thirteen thousand, eight hundred fifty-nine".