3981631 has 4 divisors (see below), whose sum is σ = 4010832. Its totient is φ = 3952432.

The previous prime is 3981629. The next prime is 3981641. The reversal of 3981631 is 1361893.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1361893 = 13 ⋅104761.

It is a cyclic number.

It is not a de Polignac number, because 3981631 - 2¹ = 3981629 is a prime.

It is a super-2 number, since 2×3981631² = 31706770840322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3981593 and 3981602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3981641) 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, 14395 + ... + 14668.

It is an arithmetic number, because the mean of its divisors is an integer number (1002708).

Almost surely, 2^3981631 is an apocalyptic number.

3981631 is a deficient number, since it is larger than the sum of its proper divisors (29201).

3981631 is a wasteful number, since it uses less digits than its factorization.

3981631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29200.

The product of its digits is 3888, while the sum is 31.

The square root of 3981631 is about 1995.4024656695. The cubic root of 3981631 is about 158.4967408698.

The spelling of 3981631 in words is "three million, nine hundred eighty-one thousand, six hundred thirty-one".