15966777997 has 8 divisors (see below), whose sum is σ = 16669393344. Its totient is φ = 15264863328.

The previous prime is 15966777991. The next prime is 15966778019. The reversal of 15966777997 is 79977766951.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 15966777997 - 2²⁷ = 15832560269 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 (15966777991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 128323 + ... + 220000.

It is an arithmetic number, because the mean of its divisors is an integer number (2083674168).

Almost surely, 2^15966777997 is an apocalyptic number.

It is an amenable number.

15966777997 is a deficient number, since it is larger than the sum of its proper divisors (702615347).

15966777997 is a wasteful number, since it uses less digits than its factorization.

15966777997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 350339.

The product of its digits is 315059220, while the sum is 73.

The spelling of 15966777997 in words is "fifteen billion, nine hundred sixty-six million, seven hundred seventy-seven thousand, nine hundred ninety-seven".