21731010640 has 40 divisors (see below), whose sum is σ = 50922455040. Its totient is φ = 8623956096.

The previous prime is 21731010629. The next prime is 21731010643. The reversal of 21731010640 is 4601013712.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731010643) 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, 1059280 + ... + 1079599.

It is an arithmetic number, because the mean of its divisors is an integer number (1273061376).

Almost surely, 2^21731010640 is an apocalyptic number.

21731010640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21731010640 is an abundant number, since it is smaller than the sum of its proper divisors (29191444400).

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

21731010640 is a wasteful number, since it uses less digits than its factorization.

21731010640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2139019 (or 2139013 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 25.

The spelling of 21731010640 in words is "twenty-one billion, seven hundred thirty-one million, ten thousand, six hundred forty".