21431279939 has 2 divisors, whose sum is σ = 21431279940. Its totient is φ = 21431279938.

The previous prime is 21431279861. The next prime is 21431280029. The reversal of 21431279939 is 93997213412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21431279939 is a prime.

It is not a weakly prime, because it can be changed into another prime (21431279339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715639969 + 10715639970.

It is an arithmetic number, because the mean of its divisors is an integer number (10715639970).

Almost surely, 2^21431279939 is an apocalyptic number.

21431279939 is a deficient number, since it is larger than the sum of its proper divisors (1).

21431279939 is an equidigital number, since it uses as much as digits as its factorization.

21431279939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 734832, while the sum is 50.

The spelling of 21431279939 in words is "twenty-one billion, four hundred thirty-one million, two hundred seventy-nine thousand, nine hundred thirty-nine".