21885018931 has 2 divisors, whose sum is σ = 21885018932. Its totient is φ = 21885018930.

The previous prime is 21885018893. The next prime is 21885018937. The reversal of 21885018931 is 13981058812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21885018931 - 2⁷ = 21885018803 is a prime.

It is a super-2 number, since 2×21885018931² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21885018937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10942509465 + 10942509466.

It is an arithmetic number, because the mean of its divisors is an integer number (10942509466).

Almost surely, 2^21885018931 is an apocalyptic number.

21885018931 is a deficient number, since it is larger than the sum of its proper divisors (1).

21885018931 is an equidigital number, since it uses as much as digits as its factorization.

21885018931 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 138240, while the sum is 46.

The spelling of 21885018931 in words is "twenty-one billion, eight hundred eighty-five million, eighteen thousand, nine hundred thirty-one".