3991668579728 has 20 divisors (see below), whose sum is σ = 7735790978508. Its totient is φ = 1995335424000.

The previous prime is 3991668579713. The next prime is 3991668579737. The reversal of 3991668579728 is 8279758661993.

It can be written as a sum of positive squares in 2 ways, for example, as 139194655744 + 3852473923984 = 373088^2 + 1962772^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31113101 + ... + 31241132.

Almost surely, 2^{3991668579728} is an apocalyptic number.

It is an amenable number.

3991668579728 is a deficient number, since it is larger than the sum of its proper divisors (3744122398780).

3991668579728 is a wasteful number, since it uses less digits than its factorization.

3991668579728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62358242 (or 62358236 counting only the distinct ones).

The product of its digits is 2469035520, while the sum is 80.

The spelling of 3991668579728 in words is "three trillion, nine hundred ninety-one billion, six hundred sixty-eight million, five hundred seventy-nine thousand, seven hundred twenty-eight".