3991585398172 has 6 divisors (see below), whose sum is σ = 6985274446808. Its totient is φ = 1995792699084.

The previous prime is 3991585398131. The next prime is 3991585398187. The reversal of 3991585398172 is 2718935851993.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498948174768 + ... + 498948174775.

Almost surely, 2^{3991585398172} is an apocalyptic number.

It is an amenable number.

3991585398172 is a deficient number, since it is larger than the sum of its proper divisors (2993689048636).

3991585398172 is a wasteful number, since it uses less digits than its factorization.

3991585398172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 997896349547 (or 997896349545 counting only the distinct ones).

The product of its digits is 146966400, while the sum is 70.

The spelling of 3991585398172 in words is "three trillion, nine hundred ninety-one billion, five hundred eighty-five million, three hundred ninety-eight thousand, one hundred seventy-two".