21216520452 has 12 divisors (see below), whose sum is σ = 49505214416. Its totient is φ = 7072173480.

The previous prime is 21216520441. The next prime is 21216520483. The reversal of 21216520452 is 25402561212.

It is a tau number, because it is divible by the number of its divisors (12).

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, 884021674 + ... + 884021697.

Almost surely, 2^21216520452 is an apocalyptic number.

It is an amenable number.

21216520452 is an abundant number, since it is smaller than the sum of its proper divisors (28288693964).

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

21216520452 is a wasteful number, since it uses less digits than its factorization.

21216520452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1768043378 (or 1768043376 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The spelling of 21216520452 in words is "twenty-one billion, two hundred sixteen million, five hundred twenty thousand, four hundred fifty-two".