3972991 has 16 divisors (see below), whose sum is σ = 4571136. Its totient is φ = 3420000.

The previous prime is 3972979. The next prime is 3973007. The reversal of 3972991 is 1992793.

It is a cyclic number.

It is not a de Polignac number, because 3972991 - 2⁵ = 3972959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3972901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20706 + ... + 20896.

It is an arithmetic number, because the mean of its divisors is an integer number (285696).

Almost surely, 2^3972991 is an apocalyptic number.

3972991 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

3972991 is a deficient number, since it is larger than the sum of its proper divisors (598145).

3972991 is a wasteful number, since it uses less digits than its factorization.

3972991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294.

The product of its digits is 30618, while the sum is 40.

The square root of 3972991 is about 1993.2363131350. The cubic root of 3972991 is about 158.3820137172.

The spelling of 3972991 in words is "three million, nine hundred seventy-two thousand, nine hundred ninety-one".