21133236864 has 32 divisors (see below), whose sum is σ = 56135161440. Its totient is φ = 7044412160.

The previous prime is 21133236853. The next prime is 21133236881. The reversal of 21133236864 is 46863233112.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×21133236864² (a number of 21 digits) contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

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, 27516852 + ... + 27517619.

It is an arithmetic number, because the mean of its divisors is an integer number (1754223795).

Almost surely, 2^21133236864 is an apocalyptic number.

21133236864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21133236864 is an abundant number, since it is smaller than the sum of its proper divisors (35001924576).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21133236864 is an equidigital number, since it uses as much as digits as its factorization.

21133236864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55034488 (or 55034476 counting only the distinct ones).

The product of its digits is 124416, while the sum is 39.

Adding to 21133236864 its reverse (46863233112), we get a palindrome (67996469976).

The spelling of 21133236864 in words is "twenty-one billion, one hundred thirty-three million, two hundred thirty-six thousand, eight hundred sixty-four".