21537760667 has 2 divisors, whose sum is σ = 21537760668. Its totient is φ = 21537760666.

The previous prime is 21537760627. The next prime is 21537760691. The reversal of 21537760667 is 76606773512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21537760667 is a prime.

It is not a weakly prime, because it can be changed into another prime (21537760627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10768880333 + 10768880334.

It is an arithmetic number, because the mean of its divisors is an integer number (10768880334).

Almost surely, 2^21537760667 is an apocalyptic number.

21537760667 is a deficient number, since it is larger than the sum of its proper divisors (1).

21537760667 is an equidigital number, since it uses as much as digits as its factorization.

21537760667 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2222640, while the sum is 50.

The spelling of 21537760667 in words is "twenty-one billion, five hundred thirty-seven million, seven hundred sixty thousand, six hundred sixty-seven".