21731504359 has 2 divisors, whose sum is σ = 21731504360. Its totient is φ = 21731504358.

The previous prime is 21731504357. The next prime is 21731504369. The reversal of 21731504359 is 95340513712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21731504359 - 2¹ = 21731504357 is a prime.

Together with 21731504357, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21731504357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10865752179 + 10865752180.

It is an arithmetic number, because the mean of its divisors is an integer number (10865752180).

Almost surely, 2^21731504359 is an apocalyptic number.

21731504359 is a deficient number, since it is larger than the sum of its proper divisors (1).

21731504359 is an equidigital number, since it uses as much as digits as its factorization.

21731504359 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 113400, while the sum is 40.

The spelling of 21731504359 in words is "twenty-one billion, seven hundred thirty-one million, five hundred four thousand, three hundred fifty-nine".