3900661 has 4 divisors (see below), whose sum is σ = 3940972. Its totient is φ = 3860352.

The previous prime is 3900649. The next prime is 3900679. The reversal of 3900661 is 1660093.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1660093 = 73 ⋅22741.

It can be written as a sum of positive squares in 2 ways, for example, as 1739761 + 2160900 = 1319^2 + 1470^2 .

It is a cyclic number.

It is not a de Polignac number, because 3900661 - 2¹⁷ = 3769589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3900691) 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 in 3 ways as a sum of consecutive naturals, for example, 20010 + ... + 20203.

It is an arithmetic number, because the mean of its divisors is an integer number (985243).

Almost surely, 2^3900661 is an apocalyptic number.

It is an amenable number.

3900661 is a deficient number, since it is larger than the sum of its proper divisors (40311).

3900661 is an equidigital number, since it uses as much as digits as its factorization.

3900661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40310.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 3900661 is about 1975.0091139030. The cubic root of 3900661 is about 157.4149839323.

The spelling of 3900661 in words is "three million, nine hundred thousand, six hundred sixty-one".