31325561 has 4 divisors (see below), whose sum is σ = 31484772. Its totient is φ = 31166352.

The previous prime is 31325557. The next prime is 31325603. The reversal of 31325561 is 16552313.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26677225 + 4648336 = 5165^2 + 2156^2 .

It is a cyclic number.

It is not a de Polignac number, because 31325561 - 2² = 31325557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 31325561.

It is not an unprimeable number, because it can be changed into a prime (31325501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79310 + ... + 79703.

It is an arithmetic number, because the mean of its divisors is an integer number (7871193).

Almost surely, 2^31325561 is an apocalyptic number.

It is an amenable number.

31325561 is a deficient number, since it is larger than the sum of its proper divisors (159211).

31325561 is a wasteful number, since it uses less digits than its factorization.

31325561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159210.

The product of its digits is 2700, while the sum is 26.

The square root of 31325561 is about 5596.9242446186. The cubic root of 31325561 is about 315.2339271856.

Adding to 31325561 its reverse (16552313), we get a palindrome (47877874).

The spelling of 31325561 in words is "thirty-one million, three hundred twenty-five thousand, five hundred sixty-one".