3990881 has 4 divisors (see below), whose sum is σ = 3996564. Its totient is φ = 3985200.

The previous prime is 3990863. The next prime is 3990901. The reversal of 3990881 is 1880993.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2512225 + 1478656 = 1585^2 + 1216^2 .

It is a cyclic number.

It is not a de Polignac number, because 3990881 - 2¹⁰ = 3989857 is a prime.

It is a super-2 number, since 2×3990881² = 31854262312322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3990841) 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, 1610 + ... + 3251.

It is an arithmetic number, because the mean of its divisors is an integer number (999141).

Almost surely, 2^3990881 is an apocalyptic number.

It is an amenable number.

3990881 is a deficient number, since it is larger than the sum of its proper divisors (5683).

3990881 is an equidigital number, since it uses as much as digits as its factorization.

3990881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5682.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 3990881 is about 1997.7189492018. The cubic root of 3990881 is about 158.6193841608.

The spelling of 3990881 in words is "three million, nine hundred ninety thousand, eight hundred eighty-one".