3972391 has 4 divisors (see below), whose sum is σ = 4109400. Its totient is φ = 3835384.

The previous prime is 3972377. The next prime is 3972413. The reversal of 3972391 is 1932793.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1932793 = 239 ⋅8087.

It is a cyclic number.

It is not a de Polignac number, because 3972391 - 2⁵ = 3972359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3972301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68461 + ... + 68518.

It is an arithmetic number, because the mean of its divisors is an integer number (1027350).

Almost surely, 2^3972391 is an apocalyptic number.

3972391 is a deficient number, since it is larger than the sum of its proper divisors (137009).

3972391 is a wasteful number, since it uses less digits than its factorization.

3972391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137008.

The product of its digits is 10206, while the sum is 34.

The square root of 3972391 is about 1993.0857984542. The cubic root of 3972391 is about 158.3740403799.

The spelling of 3972391 in words is "three million, nine hundred seventy-two thousand, three hundred ninety-one".