21319597939 has 2 divisors, whose sum is σ = 21319597940. Its totient is φ = 21319597938.

The previous prime is 21319597931. The next prime is 21319597961. The reversal of 21319597939 is 93979591312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21319597939 - 2³ = 21319597931 is a prime.

It is a super-2 number, since 2×21319597939² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21319597931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10659798969 + 10659798970.

It is an arithmetic number, because the mean of its divisors is an integer number (10659798970).

Almost surely, 2^21319597939 is an apocalyptic number.

21319597939 is a deficient number, since it is larger than the sum of its proper divisors (1).

21319597939 is an equidigital number, since it uses as much as digits as its factorization.

21319597939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4133430, while the sum is 58.

The spelling of 21319597939 in words is "twenty-one billion, three hundred nineteen million, five hundred ninety-seven thousand, nine hundred thirty-nine".