3181561 has 8 divisors (see below), whose sum is σ = 3398400. Its totient is φ = 2971920.

The previous prime is 3181543. The next prime is 3181573. The reversal of 3181561 is 1651813.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3181561 - 2⁹ = 3181049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3181501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 871 + ... + 2668.

It is an arithmetic number, because the mean of its divisors is an integer number (424800).

Almost surely, 2^3181561 is an apocalyptic number.

3181561 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

3181561 is a deficient number, since it is larger than the sum of its proper divisors (216839).

3181561 is a wasteful number, since it uses less digits than its factorization.

3181561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3599.

The product of its digits is 720, while the sum is 25.

The square root of 3181561 is about 1783.6930789797. The cubic root of 3181561 is about 147.0776734833.

The spelling of 3181561 in words is "three million, one hundred eighty-one thousand, five hundred sixty-one".