21391358839 has 2 divisors, whose sum is σ = 21391358840. Its totient is φ = 21391358838.

The previous prime is 21391358837. The next prime is 21391358869. The reversal of 21391358839 is 93885319312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21391358839 - 2¹ = 21391358837 is a prime.

Together with 21391358837, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21391358837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10695679419 + 10695679420.

It is an arithmetic number, because the mean of its divisors is an integer number (10695679420).

Almost surely, 2^21391358839 is an apocalyptic number.

21391358839 is a deficient number, since it is larger than the sum of its proper divisors (1).

21391358839 is an equidigital number, since it uses as much as digits as its factorization.

21391358839 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1399680, while the sum is 52.

The spelling of 21391358839 in words is "twenty-one billion, three hundred ninety-one million, three hundred fifty-eight thousand, eight hundred thirty-nine".