21913885 has 16 divisors (see below), whose sum is σ = 30788352. Its totient is φ = 14659200.

The previous prime is 21913861. The next prime is 21913933. The reversal of 21913885 is 58831912.

It is not a de Polignac number, because 21913885 - 2¹¹ = 21911837 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6201 + ... + 9070.

It is an arithmetic number, because the mean of its divisors is an integer number (1924272).

Almost surely, 2^21913885 is an apocalyptic number.

It is an amenable number.

21913885 is a deficient number, since it is larger than the sum of its proper divisors (8874467).

21913885 is a wasteful number, since it uses less digits than its factorization.

21913885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15324.

The product of its digits is 17280, while the sum is 37.

The square root of 21913885 is about 4681.2268691017. The cubic root of 21913885 is about 279.8378525474.

The spelling of 21913885 in words is "twenty-one million, nine hundred thirteen thousand, eight hundred eighty-five".