21913894 has 16 divisors (see below), whose sum is σ = 34408800. Its totient is φ = 10447360.

The previous prime is 21913861. The next prime is 21913933. The reversal of 21913894 is 49831912.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20124 + ... + 21184.

It is an arithmetic number, because the mean of its divisors is an integer number (2150550).

Almost surely, 2^21913894 is an apocalyptic number.

21913894 is a deficient number, since it is larger than the sum of its proper divisors (12494906).

21913894 is a wasteful number, since it uses less digits than its factorization.

21913894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1535.

The product of its digits is 15552, while the sum is 37.

The square root of 21913894 is about 4681.2278303881. The cubic root of 21913894 is about 279.8378908571.

The spelling of 21913894 in words is "twenty-one million, nine hundred thirteen thousand, eight hundred ninety-four".