21356450 has 24 divisors (see below), whose sum is σ = 40125780. Its totient is φ = 8456000.

The previous prime is 21356431. The next prime is 21356453. The reversal of 21356450 is 5465312.

It can be written as a sum of positive squares in 6 ways, for example, as 19811401 + 1545049 = 4451^2 + 1243^2 .

It is a hoax number, since the sum of its digits (26) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21356453) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2936 + ... + 7164.

Almost surely, 2^21356450 is an apocalyptic number.

21356450 is a deficient number, since it is larger than the sum of its proper divisors (18769330).

21356450 is a wasteful number, since it uses less digits than its factorization.

21356450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4342 (or 4337 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 21356450 is about 4621.3039285466. The cubic root of 21356450 is about 277.4446498377. Note that the first 3 decimals are identical.

The spelling of 21356450 in words is "twenty-one million, three hundred fifty-six thousand, four hundred fifty".