3991318168509 has 48 divisors (see below), whose sum is σ = 6976660728960. Its totient is φ = 2146517729280.

The previous prime is 3991318168499. The next prime is 3991318168511. The reversal of 3991318168509 is 9058618131993.

3991318168509 is a `hidden beast` number, since 3 + 9 + 91 + 31 + 8 + 1 + 6 + 8 + 509 = 666.

3991318168509 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 3991318168509 - 2¹³ = 3991318160317 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991318168109) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 48302589 + ... + 48385149.

It is an arithmetic number, because the mean of its divisors is an integer number (145347098520).

Almost surely, 2^{3991318168509} is an apocalyptic number.

It is an amenable number.

3991318168509 is a deficient number, since it is larger than the sum of its proper divisors (2985342560451).

3991318168509 is a wasteful number, since it uses less digits than its factorization.

3991318168509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127730 (or 127727 counting only the distinct ones).

The product of its (nonzero) digits is 12597120, while the sum is 63.

The spelling of 3991318168509 in words is "three trillion, nine hundred ninety-one billion, three hundred eighteen million, one hundred sixty-eight thousand, five hundred nine".