21534948864 has 360 divisors, whose sum is σ = 73594857336. Its totient is φ = 6021734400.

The previous prime is 21534948833. The next prime is 21534948881. The reversal of 21534948864 is 46884943512.

21534948864 is a `hidden beast` number, since 2 + 1 + 534 + 9 + 48 + 8 + 64 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21534948864.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7246899 + ... + 7249869.

Almost surely, 2^21534948864 is an apocalyptic number.

21534948864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21534948864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36797428668).

21534948864 is an abundant number, since it is smaller than the sum of its proper divisors (52059908472).

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

21534948864 is a wasteful number, since it uses less digits than its factorization.

21534948864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030 (or 3000 counting only the distinct ones).

The product of its digits is 6635520, while the sum is 54.

The spelling of 21534948864 in words is "twenty-one billion, five hundred thirty-four million, nine hundred forty-eight thousand, eight hundred sixty-four".