21867902891 has 2 divisors, whose sum is σ = 21867902892. Its totient is φ = 21867902890.

The previous prime is 21867902843. The next prime is 21867902909. The reversal of 21867902891 is 19820976812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21867902891 is a prime.

It is not a weakly prime, because it can be changed into another prime (21867902821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10933951445 + 10933951446.

It is an arithmetic number, because the mean of its divisors is an integer number (10933951446).

Almost surely, 2^21867902891 is an apocalyptic number.

21867902891 is a deficient number, since it is larger than the sum of its proper divisors (1).

21867902891 is an equidigital number, since it uses as much as digits as its factorization.

21867902891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 53.

The spelling of 21867902891 in words is "twenty-one billion, eight hundred sixty-seven million, nine hundred two thousand, eight hundred ninety-one".