3999581 has 2 divisors, whose sum is σ = 3999582. Its totient is φ = 3999580.

The previous prime is 3999577. The next prime is 3999599. The reversal of 3999581 is 1859993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3496900 + 502681 = 1870^2 + 709^2 .

It is a cyclic number.

It is not a de Polignac number, because 3999581 - 2² = 3999577 is a prime.

It is a super-2 number, since 2×3999581² = 31993296351122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3999511) 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 as a sum of consecutive naturals, namely, 1999790 + 1999791.

It is an arithmetic number, because the mean of its divisors is an integer number (1999791).

Almost surely, 2^3999581 is an apocalyptic number.

It is an amenable number.

3999581 is a deficient number, since it is larger than the sum of its proper divisors (1).

3999581 is an equidigital number, since it uses as much as digits as its factorization.

3999581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 87480, while the sum is 44.

The square root of 3999581 is about 1999.8952472567. The cubic root of 3999581 is about 158.7345623279.

The spelling of 3999581 in words is "three million, nine hundred ninety-nine thousand, five hundred eighty-one".