21587320460 has 24 divisors (see below), whose sum is σ = 48000042720. Its totient is φ = 8126991104.

The previous prime is 21587320429. The next prime is 21587320523. The reversal of 21587320460 is 6402378512.

It is a happy number.

It is a super-2 number, since 2×21587320460² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31745720 + ... + 31746399.

It is an arithmetic number, because the mean of its divisors is an integer number (2000001780).

Almost surely, 2^21587320460 is an apocalyptic number.

21587320460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21587320460 is an abundant number, since it is smaller than the sum of its proper divisors (26412722260).

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

21587320460 is a wasteful number, since it uses less digits than its factorization.

21587320460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63492145 (or 63492143 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 38.

Adding to 21587320460 its reverse (6402378512), we get a palindrome (27989698972).

The spelling of 21587320460 in words is "twenty-one billion, five hundred eighty-seven million, three hundred twenty thousand, four hundred sixty".