3903991 has 8 divisors (see below), whose sum is σ = 4805024. Its totient is φ = 3088800.

The previous prime is 3903973. The next prime is 3904001. The reversal of 3903991 is 1993093.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3903991 - 2⁹ = 3903479 is a prime.

It is a super-2 number, since 2×3903991² = 30482291456162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3903901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21360 + ... + 21541.

It is an arithmetic number, because the mean of its divisors is an integer number (600628).

Almost surely, 2^3903991 is an apocalyptic number.

3903991 is a deficient number, since it is larger than the sum of its proper divisors (901033).

3903991 is a wasteful number, since it uses less digits than its factorization.

3903991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42921.

The product of its (nonzero) digits is 6561, while the sum is 34.

The square root of 3903991 is about 1975.8519681393. The cubic root of 3903991 is about 157.4597663251.

The spelling of 3903991 in words is "three million, nine hundred three thousand, nine hundred ninety-one".