3999631 has 4 divisors (see below), whose sum is σ = 4173552. Its totient is φ = 3825712.

The previous prime is 3999629. The next prime is 3999637. The reversal of 3999631 is 1369993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1369993 = 353 ⋅3881.

It is a cyclic number.

It is not a de Polignac number, because 3999631 - 2¹ = 3999629 is a prime.

It is a super-2 number, since 2×3999631² = 31994096272322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3999637) 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, 86926 + ... + 86971.

It is an arithmetic number, because the mean of its divisors is an integer number (1043388).

Almost surely, 2^3999631 is an apocalyptic number.

3999631 is a deficient number, since it is larger than the sum of its proper divisors (173921).

3999631 is a wasteful number, since it uses less digits than its factorization.

3999631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173920.

The product of its digits is 39366, while the sum is 40.

The square root of 3999631 is about 1999.9077478724. The cubic root of 3999631 is about 158.7352237885.

The spelling of 3999631 in words is "three million, nine hundred ninety-nine thousand, six hundred thirty-one".