3973991 has 12 divisors (see below), whose sum is σ = 4658448. Its totient is φ = 3320832.

The previous prime is 3973973. The next prime is 3973997. The reversal of 3973991 is 1993793.

It is not a de Polignac number, because 3973991 - 2⁶ = 3973927 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 (3973997) 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 11 ways as a sum of consecutive naturals, for example, 15335 + ... + 15591.

It is an arithmetic number, because the mean of its divisors is an integer number (388204).

Almost surely, 2^3973991 is an apocalyptic number.

3973991 is a deficient number, since it is larger than the sum of its proper divisors (684457).

3973991 is an equidigital number, since it uses as much as digits as its factorization.

3973991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358 (or 311 counting only the distinct ones).

The product of its digits is 45927, while the sum is 41.

The square root of 3973991 is about 1993.4871456822. The cubic root of 3973991 is about 158.3953008290.

The spelling of 3973991 in words is "three million, nine hundred seventy-three thousand, nine hundred ninety-one".