21987817060 has 48 divisors (see below), whose sum is σ = 50437981440. Its totient is φ = 7985111040.

The previous prime is 21987817043. The next prime is 21987817067. The reversal of 21987817060 is 6071878912.

It is a junction number, because it is equal to n+sod(n) for n = 21987816995 and 21987817013.

It is not an unprimeable number, because it can be changed into a prime (21987817067) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 104197 + ... + 234163.

It is an arithmetic number, because the mean of its divisors is an integer number (1050791280).

Almost surely, 2^21987817060 is an apocalyptic number.

21987817060 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21987817060 is an abundant number, since it is smaller than the sum of its proper divisors (28450164380).

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

21987817060 is a wasteful number, since it uses less digits than its factorization.

21987817060 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130756 (or 130754 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 49.

The spelling of 21987817060 in words is "twenty-one billion, nine hundred eighty-seven million, eight hundred seventeen thousand, sixty".