21637632899 has 2 divisors, whose sum is σ = 21637632900. Its totient is φ = 21637632898.

The previous prime is 21637632883. The next prime is 21637633013. The reversal of 21637632899 is 99823673612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21637632899 - 2⁴ = 21637632883 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21637632299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10818816449 + 10818816450.

It is an arithmetic number, because the mean of its divisors is an integer number (10818816450).

Almost surely, 2^21637632899 is an apocalyptic number.

21637632899 is a deficient number, since it is larger than the sum of its proper divisors (1).

21637632899 is an equidigital number, since it uses as much as digits as its factorization.

21637632899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5878656, while the sum is 56.

The spelling of 21637632899 in words is "twenty-one billion, six hundred thirty-seven million, six hundred thirty-two thousand, eight hundred ninety-nine".