3991876290681 has 24 divisors (see below), whose sum is σ = 5655745911840. Its totient is φ = 2503936369152.

The previous prime is 3991876290631. The next prime is 3991876290683. The reversal of 3991876290681 is 1860926781993.

3991876290681 is a nontrivial binomial coefficient, being equal to C(2825554, 2).

It is not a de Polignac number, because 3991876290681 - 2¹⁰ = 3991876289657 is a prime.

It is a super-2 number, since 2×3991876290681² (a number of 26 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (3991876290683) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2119165 + ... + 3531941.

It is an arithmetic number, because the mean of its divisors is an integer number (235656079660).

Almost surely, 2^{3991876290681} is an apocalyptic number.

3991876290681 is the 2825553-rd triangular number and also the 1412777-th hexagonal number.

It is an amenable number.

3991876290681 is a deficient number, since it is larger than the sum of its proper divisors (1663869621159).

3991876290681 is a wasteful number, since it uses less digits than its factorization.

3991876290681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1416073 (or 1416056 counting only the distinct ones).

The product of its (nonzero) digits is 70543872, while the sum is 69.

The spelling of 3991876290681 in words is "three trillion, nine hundred ninety-one billion, eight hundred seventy-six million, two hundred ninety thousand, six hundred eighty-one".