3901661 has 2 divisors, whose sum is σ = 3901662. Its totient is φ = 3901660.

The previous prime is 3901657. The next prime is 3901673. The reversal of 3901661 is 1661093.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3308761 + 592900 = 1819^2 + 770^2 .

It is a cyclic number.

It is not a de Polignac number, because 3901661 - 2² = 3901657 is a prime.

It is equal to p₂₇₆₇₁₃ and since 3901661 and 276713 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 3901661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3901561) 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, 1950830 + 1950831.

It is an arithmetic number, because the mean of its divisors is an integer number (1950831).

Almost surely, 2^3901661 is an apocalyptic number.

It is an amenable number.

3901661 is a deficient number, since it is larger than the sum of its proper divisors (1).

3901661 is an equidigital number, since it uses as much as digits as its factorization.

3901661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 3901661 is about 1975.2622610681. The cubic root of 3901661 is about 157.4284347751.

The spelling of 3901661 in words is "three million, nine hundred one thousand, six hundred sixty-one".