3990505 has 4 divisors (see below), whose sum is σ = 4788612. Its totient is φ = 3192400.

The previous prime is 3990473. The next prime is 3990509. The reversal of 3990505 is 5050993.

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 2442969 + 1547536 = 1563^2 + 1244^2 .

It is not a de Polignac number, because 3990505 - 2⁵ = 3990473 is a prime.

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 a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3990509) 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, 399046 + ... + 399055.

It is an arithmetic number, because the mean of its divisors is an integer number (1197153).

Almost surely, 2^3990505 is an apocalyptic number.

It is an amenable number.

3990505 is a deficient number, since it is larger than the sum of its proper divisors (798107).

3990505 is an equidigital number, since it uses as much as digits as its factorization.

3990505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798106.

The product of its (nonzero) digits is 6075, while the sum is 31.

The square root of 3990505 is about 1997.6248396533. The cubic root of 3990505 is about 158.6144025739.

The spelling of 3990505 in words is "three million, nine hundred ninety thousand, five hundred five".