21532267657 has 2 divisors, whose sum is σ = 21532267658. Its totient is φ = 21532267656.

The previous prime is 21532267639. The next prime is 21532267661. The reversal of 21532267657 is 75676223512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20214868041 + 1317399616 = 142179^2 + 36296^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21532267657 is a prime.

It is not a weakly prime, because it can be changed into another prime (21532267637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10766133828 + 10766133829.

It is an arithmetic number, because the mean of its divisors is an integer number (10766133829).

Almost surely, 2^21532267657 is an apocalyptic number.

It is an amenable number.

21532267657 is a deficient number, since it is larger than the sum of its proper divisors (1).

21532267657 is an equidigital number, since it uses as much as digits as its factorization.

21532267657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1058400, while the sum is 46.

The spelling of 21532267657 in words is "twenty-one billion, five hundred thirty-two million, two hundred sixty-seven thousand, six hundred fifty-seven".