21664354 has 8 divisors (see below), whose sum is σ = 32530140. Its totient is φ = 10820976.

The previous prime is 21664343. The next prime is 21664361. The reversal of 21664354 is 45346612.

It can be written as a sum of positive squares in 2 ways, for example, as 21206025 + 458329 = 4605^2 + 677^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2929 + ... + 7204.

Almost surely, 2^21664354 is an apocalyptic number.

21664354 is a deficient number, since it is larger than the sum of its proper divisors (10865786).

21664354 is a wasteful number, since it uses less digits than its factorization.

21664354 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11204.

The product of its digits is 17280, while the sum is 31.

The square root of 21664354 is about 4654.4982543772. The cubic root of 21664354 is about 278.7716343213.

The spelling of 21664354 in words is "twenty-one million, six hundred sixty-four thousand, three hundred fifty-four".