3131561 has 8 divisors (see below), whose sum is σ = 3373920. Its totient is φ = 2896992.

The previous prime is 3131551. The next prime is 3131593. The reversal of 3131561 is 1651313.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 3131561 - 2⁶ = 3131497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3131501) 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, 1100 + ... + 2733.

It is an arithmetic number, because the mean of its divisors is an integer number (421740).

Almost surely, 2^3131561 is an apocalyptic number.

It is an amenable number.

3131561 is a deficient number, since it is larger than the sum of its proper divisors (242359).

3131561 is a wasteful number, since it uses less digits than its factorization.

3131561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3895.

The product of its digits is 270, while the sum is 20.

The square root of 3131561 is about 1769.6217109880. The cubic root of 3131561 is about 146.3031326171.

Adding to 3131561 its reverse (1651313), we get a palindrome (4782874).

The spelling of 3131561 in words is "three million, one hundred thirty-one thousand, five hundred sixty-one".