21509294752 has 48 divisors (see below), whose sum is σ = 46210645152. Its totient is φ = 9773873920.

The previous prime is 21509294747. The next prime is 21509294759. The reversal of 21509294752 is 25749290512.

It is not an unprimeable number, because it can be changed into a prime (21509294759) 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, 1404963 + ... + 1420189.

It is an arithmetic number, because the mean of its divisors is an integer number (962721774).

Almost surely, 2^21509294752 is an apocalyptic number.

21509294752 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21509294752 is an abundant number, since it is smaller than the sum of its proper divisors (24701350400).

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

21509294752 is a wasteful number, since it uses less digits than its factorization.

21509294752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19261 (or 19253 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 46.

The spelling of 21509294752 in words is "twenty-one billion, five hundred nine million, two hundred ninety-four thousand, seven hundred fifty-two".