3999931 has 4 divisors (see below), whose sum is σ = 4307632. Its totient is φ = 3692232.

The previous prime is 3999929. The next prime is 3999949. The reversal of 3999931 is 1399993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1399993 = 7 ⋅199999.

It is a cyclic number.

It is not a de Polignac number, because 3999931 - 2¹ = 3999929 is a prime.

It is a super-2 number, since 2×3999931² = 31998896009522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3999901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 153831 + ... + 153856.

It is an arithmetic number, because the mean of its divisors is an integer number (1076908).

Almost surely, 2^3999931 is an apocalyptic number.

3999931 is a deficient number, since it is larger than the sum of its proper divisors (307701).

3999931 is a wasteful number, since it uses less digits than its factorization.

3999931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307700.

The product of its digits is 59049, while the sum is 43.

The square root of 3999931 is about 1999.9827499256. The cubic root of 3999931 is about 158.7391924360.

The spelling of 3999931 in words is "three million, nine hundred ninety-nine thousand, nine hundred thirty-one".