3181405661 has 4 divisors (see below), whose sum is σ = 3635892192. Its totient is φ = 2726919132.

The previous prime is 3181405649. The next prime is 3181405727. The reversal of 3181405661 is 1665041813.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 3181405661 - 2³⁰ = 2107663837 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 (3181405621) 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, 227243255 + ... + 227243268.

It is an arithmetic number, because the mean of its divisors is an integer number (908973048).

Almost surely, 2^3181405661 is an apocalyptic number.

It is an amenable number.

3181405661 is a deficient number, since it is larger than the sum of its proper divisors (454486531).

3181405661 is an equidigital number, since it uses as much as digits as its factorization.

3181405661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454486530.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 3181405661 is about 56403.9507570170. The cubic root of 3181405661 is about 1470.7527976626.

The spelling of 3181405661 in words is "three billion, one hundred eighty-one million, four hundred five thousand, six hundred sixty-one".