21521975480 has 32 divisors (see below), whose sum is σ = 48852990000. Its totient is φ = 8532604416.

The previous prime is 21521975479. The next prime is 21521975483. The reversal of 21521975480 is 8457912512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521975483) 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, 2376230 + ... + 2385269.

Almost surely, 2^21521975480 is an apocalyptic number.

21521975480 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21521975480 is an abundant number, since it is smaller than the sum of its proper divisors (27331014520).

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

21521975480 is a wasteful number, since it uses less digits than its factorization.

21521975480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4761623 (or 4761619 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 44.

The spelling of 21521975480 in words is "twenty-one billion, five hundred twenty-one million, nine hundred seventy-five thousand, four hundred eighty".