21531502550 has 12 divisors (see below), whose sum is σ = 40048594836. Its totient is φ = 8612601000.

The previous prime is 21531502523. The next prime is 21531502567. The reversal of 21531502550 is 5520513512.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215314976 + ... + 215315075.

It is an arithmetic number, because the mean of its divisors is an integer number (3337382903).

Almost surely, 2^21531502550 is an apocalyptic number.

21531502550 is a deficient number, since it is larger than the sum of its proper divisors (18517092286).

21531502550 is a wasteful number, since it uses less digits than its factorization.

21531502550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430630063 (or 430630058 counting only the distinct ones).

The product of its (nonzero) digits is 7500, while the sum is 29.

The spelling of 21531502550 in words is "twenty-one billion, five hundred thirty-one million, five hundred two thousand, five hundred fifty".