21664363 has 8 divisors (see below), whose sum is σ = 25613280. Its totient is φ = 17928960.

The previous prime is 21664361. The next prime is 21664373. The reversal of 21664363 is 36346612.

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

It is not a de Polignac number, because 21664363 - 2¹ = 21664361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21664361) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53158 + ... + 53563.

It is an arithmetic number, because the mean of its divisors is an integer number (3201660).

Almost surely, 2^21664363 is an apocalyptic number.

21664363 is a deficient number, since it is larger than the sum of its proper divisors (3948917).

21664363 is a wasteful number, since it uses less digits than its factorization.

21664363 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106757.

The product of its digits is 15552, while the sum is 31.

The square root of 21664363 is about 4654.4992211837. The cubic root of 21664363 is about 278.7716729246.

The spelling of 21664363 in words is "twenty-one million, six hundred sixty-four thousand, three hundred sixty-three".