3990521 has 2 divisors, whose sum is σ = 3990522. Its totient is φ = 3990520.

The previous prime is 3990509. The next prime is 3990541. The reversal of 3990521 is 1250993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3857296 + 133225 = 1964^2 + 365^2 .

It is a cyclic number.

It is not a de Polignac number, because 3990521 - 2¹⁸ = 3728377 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (3990541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1995260 + 1995261.

It is an arithmetic number, because the mean of its divisors is an integer number (1995261).

Almost surely, 2^3990521 is an apocalyptic number.

It is an amenable number.

3990521 is a deficient number, since it is larger than the sum of its proper divisors (1).

3990521 is an equidigital number, since it uses as much as digits as its factorization.

3990521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 3990521 is about 1997.6288444053. The cubic root of 3990521 is about 158.6146145626.

The spelling of 3990521 in words is "three million, nine hundred ninety thousand, five hundred twenty-one".