21356361 has 36 divisors (see below), whose sum is σ = 35209200. Its totient is φ = 12433824.

The previous prime is 21356353. The next prime is 21356381. The reversal of 21356361 is 16365312.

21356361 is a `hidden beast` number, since 21 + 3 + 5 + 636 + 1 = 666.

It is not a de Polignac number, because 21356361 - 2³ = 21356353 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21356341) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 28530 + ... + 29268.

Almost surely, 2^21356361 is an apocalyptic number.

It is an amenable number.

21356361 is a deficient number, since it is larger than the sum of its proper divisors (13852839).

21356361 is a wasteful number, since it uses less digits than its factorization.

21356361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 790 (or 774 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 21356361 is about 4621.2942992196. The cubic root of 21356361 is about 277.4442644333. Note that the first 3 decimals are identical.

The spelling of 21356361 in words is "twenty-one million, three hundred fifty-six thousand, three hundred sixty-one".