3957891 has 32 divisors (see below), whose sum is σ = 6397440. Its totient is φ = 2128896.

The previous prime is 3957883. The next prime is 3957907. The reversal of 3957891 is 1987593.

It is a happy number.

3957891 is a nontrivial binomial coefficient, being equal to C(2814, 2).

It is not a de Polignac number, because 3957891 - 2³ = 3957883 is a prime.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (3957091) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 40755 + ... + 40851.

It is an arithmetic number, because the mean of its divisors is an integer number (199920).

Almost surely, 2^3957891 is an apocalyptic number.

3957891 is the 2813-rd triangular number and also the 1407-th hexagonal number.

3957891 is a deficient number, since it is larger than the sum of its proper divisors (2439549).

3957891 is a wasteful number, since it uses less digits than its factorization.

3957891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203.

The product of its digits is 68040, while the sum is 42.

The square root of 3957891 is about 1989.4448974526. Note that the first 3 decimals coincide. The cubic root of 3957891 is about 158.1811067540.

The spelling of 3957891 in words is "three million, nine hundred fifty-seven thousand, eight hundred ninety-one".