21633862891 has 2 divisors, whose sum is σ = 21633862892. Its totient is φ = 21633862890.

The previous prime is 21633862883. The next prime is 21633862909. The reversal of 21633862891 is 19826833612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21633862891 - 2³ = 21633862883 is a prime.

It is not a weakly prime, because it can be changed into another prime (21633862841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10816931445 + 10816931446.

It is an arithmetic number, because the mean of its divisors is an integer number (10816931446).

Almost surely, 2^21633862891 is an apocalyptic number.

21633862891 is a deficient number, since it is larger than the sum of its proper divisors (1).

21633862891 is an equidigital number, since it uses as much as digits as its factorization.

21633862891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 746496, while the sum is 49.

The spelling of 21633862891 in words is "twenty-one billion, six hundred thirty-three million, eight hundred sixty-two thousand, eight hundred ninety-one".