15516319997 has 2 divisors, whose sum is σ = 15516319998. Its totient is φ = 15516319996.

The previous prime is 15516319991. The next prime is 15516320023. The reversal of 15516319997 is 79991361551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9418896601 + 6097423396 = 97051^2 + 78086^2 .

It is a cyclic number.

It is not a de Polignac number, because 15516319997 - 2⁶ = 15516319933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15516319991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7758159998 + 7758159999.

It is an arithmetic number, because the mean of its divisors is an integer number (7758159999).

Almost surely, 2^15516319997 is an apocalyptic number.

It is an amenable number.

15516319997 is a deficient number, since it is larger than the sum of its proper divisors (1).

15516319997 is an equidigital number, since it uses as much as digits as its factorization.

15516319997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2296350, while the sum is 56.

The spelling of 15516319997 in words is "fifteen billion, five hundred sixteen million, three hundred nineteen thousand, nine hundred ninety-seven".