3991523612318 has 32 divisors (see below), whose sum is σ = 6875501546880. Its totient is φ = 1718800452000.

The previous prime is 3991523612303. The next prime is 3991523612333. The reversal of 3991523612318 is 8132163251993.

It is an interprime number because it is at equal distance from previous prime (3991523612303) and next prime (3991523612333).

It is a super-2 number, since 2×3991523612318² (a number of 26 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 3991523612318.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28463153 + ... + 28603043.

It is an arithmetic number, because the mean of its divisors is an integer number (214859423340).

Almost surely, 2^{3991523612318} is an apocalyptic number.

3991523612318 is a gapful number since it is divisible by the number (38) formed by its first and last digit.

3991523612318 is a deficient number, since it is larger than the sum of its proper divisors (2883977934562).

3991523612318 is a wasteful number, since it uses less digits than its factorization.

3991523612318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208184.

The product of its digits is 2099520, while the sum is 53.

The spelling of 3991523612318 in words is "three trillion, nine hundred ninety-one billion, five hundred twenty-three million, six hundred twelve thousand, three hundred eighteen".