21813634 has 16 divisors (see below), whose sum is σ = 35095680. Its totient is φ = 10136880.

The previous prime is 21813619. The next prime is 21813643. The reversal of 21813634 is 43631812.

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, 3402 + ... + 7429.

It is an arithmetic number, because the mean of its divisors is an integer number (2193480).

Almost surely, 2^21813634 is an apocalyptic number.

21813634 is a deficient number, since it is larger than the sum of its proper divisors (13282046).

21813634 is a wasteful number, since it uses less digits than its factorization.

21813634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10905.

The product of its digits is 3456, while the sum is 28.

The square root of 21813634 is about 4670.5068247461. The cubic root of 21813634 is about 279.4104688155.

The spelling of 21813634 in words is "twenty-one million, eight hundred thirteen thousand, six hundred thirty-four".