21767123640 has 64 divisors (see below), whose sum is σ = 68140569600. Its totient is φ = 5552193152.

The previous prime is 21767123621. The next prime is 21767123683. The reversal of 21767123640 is 4632176712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3940560 + ... + 3946079.

It is an arithmetic number, because the mean of its divisors is an integer number (1064696400).

Almost surely, 2^21767123640 is an apocalyptic number.

21767123640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21767123640 is an abundant number, since it is smaller than the sum of its proper divisors (46373445960).

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

21767123640 is a wasteful number, since it uses less digits than its factorization.

21767123640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7886676 (or 7886672 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 39.

The spelling of 21767123640 in words is "twenty-one billion, seven hundred sixty-seven million, one hundred twenty-three thousand, six hundred forty".