15721239791 has 2 divisors, whose sum is σ = 15721239792. Its totient is φ = 15721239790.

The previous prime is 15721239763. The next prime is 15721239799. The reversal of 15721239791 is 19793212751.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15721239791 - 2³⁰ = 14647497967 is a prime.

It is a super-2 number, since 2×15721239791² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15721239799) 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, 7860619895 + 7860619896.

It is an arithmetic number, because the mean of its divisors is an integer number (7860619896).

Almost surely, 2^15721239791 is an apocalyptic number.

15721239791 is a deficient number, since it is larger than the sum of its proper divisors (1).

15721239791 is an equidigital number, since it uses as much as digits as its factorization.

15721239791 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 238140, while the sum is 47.

The spelling of 15721239791 in words is "fifteen billion, seven hundred twenty-one million, two hundred thirty-nine thousand, seven hundred ninety-one".