21133456 has 40 divisors (see below), whose sum is σ = 42318720. Its totient is φ = 10218624.

The previous prime is 21133451. The next prime is 21133477. The reversal of 21133456 is 65433112.

It is a self number, because there is not a number n which added to its sum of digits gives 21133456.

It is not an unprimeable number, because it can be changed into a prime (21133451) 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, 117975 + ... + 118153.

It is an arithmetic number, because the mean of its divisors is an integer number (1057968).

Almost surely, 2^21133456 is an apocalyptic number.

It is an amenable number.

21133456 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

21133456 is a wasteful number, since it uses less digits than its factorization.

21133456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 391 (or 385 counting only the distinct ones).

The product of its digits is 2160, while the sum is 25.

The square root of 21133456 is about 4597.1138772060. The cubic root of 21133456 is about 276.4756204341.

Adding to 21133456 its reverse (65433112), we get a palindrome (86566568).

The spelling of 21133456 in words is "twenty-one million, one hundred thirty-three thousand, four hundred fifty-six".