15999999997 has 4 divisors (see below), whose sum is σ = 16842105280. Its totient is φ = 15157894716.

The previous prime is 15999999991. The next prime is 16000000039. The reversal of 15999999997 is 79999999951.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 15999999997 - 2²⁷ = 15865782269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15999999991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 421052613 + ... + 421052650.

It is an arithmetic number, because the mean of its divisors is an integer number (4210526320).

Almost surely, 2^15999999997 is an apocalyptic number.

It is an amenable number.

15999999997 is a deficient number, since it is larger than the sum of its proper divisors (842105283).

15999999997 is an equidigital number, since it uses as much as digits as its factorization.

15999999997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 842105282.

The product of its digits is 1506635235, while the sum is 85.

The spelling of 15999999997 in words is "fifteen billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-seven".