3983991 has 32 divisors (see below), whose sum is σ = 6289920. Its totient is φ = 2217600.

The previous prime is 3983989. The next prime is 3983999. The reversal of 3983991 is 1993893.

3983991 = 415² + 416² + ... + 436².

It is a happy number.

It is not a de Polignac number, because 3983991 - 2¹ = 3983989 is a prime.

It is a super-3 number, since 3×3983991³ (a number of 21 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3983999) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21921 + ... + 22101.

It is an arithmetic number, because the mean of its divisors is an integer number (196560).

Almost surely, 2^3983991 is an apocalyptic number.

3983991 is a deficient number, since it is larger than the sum of its proper divisors (2305929).

3983991 is a wasteful number, since it uses less digits than its factorization.

3983991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247.

The product of its digits is 52488, while the sum is 42.

The square root of 3983991 is about 1995.9937374651. The cubic root of 3983991 is about 158.5280495161.

The spelling of 3983991 in words is "three million, nine hundred eighty-three thousand, nine hundred ninety-one".