21874858615891 has 2 divisors, whose sum is σ = 21874858615892. Its totient is φ = 21874858615890.

The previous prime is 21874858615861. The next prime is 21874858615913. The reversal of 21874858615891 is 19851685847812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21874858615891 - 2³⁵ = 21840498877523 is a prime.

It is not a weakly prime, because it can be changed into another prime (21874858615861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10937429307945 + 10937429307946.

It is an arithmetic number, because the mean of its divisors is an integer number (10937429307946).

Almost surely, 2^{21874858615891} is an apocalyptic number.

21874858615891 is a deficient number, since it is larger than the sum of its proper divisors (1).

21874858615891 is an equidigital number, since it uses as much as digits as its factorization.

21874858615891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 309657600, while the sum is 73.

The spelling of 21874858615891 in words is "twenty-one trillion, eight hundred seventy-four billion, eight hundred fifty-eight million, six hundred fifteen thousand, eight hundred ninety-one".