21634707 has 4 divisors (see below), whose sum is σ = 28846280. Its totient is φ = 14423136.

The previous prime is 21634699. The next prime is 21634729. The reversal of 21634707 is 70743612.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21634707 - 2³ = 21634699 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21634607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3605782 + ... + 3605787.

It is an arithmetic number, because the mean of its divisors is an integer number (7211570).

Almost surely, 2^21634707 is an apocalyptic number.

21634707 is a deficient number, since it is larger than the sum of its proper divisors (7211573).

21634707 is an equidigital number, since it uses as much as digits as its factorization.

21634707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7211572.

The product of its (nonzero) digits is 7056, while the sum is 30.

The square root of 21634707 is about 4651.3123954428. The cubic root of 21634707 is about 278.6444128107.

The spelling of 21634707 in words is "twenty-one million, six hundred thirty-four thousand, seven hundred seven".