31561025 has 6 divisors (see below), whose sum is σ = 39135702. Its totient is φ = 25248800.

The previous prime is 31561003. The next prime is 31561043. The reversal of 31561025 is 52016513.

It can be written as a sum of positive squares in 3 ways, for example, as 5683456 + 25877569 = 2384^2 + 5087^2 .

It is a de Polignac number, because none of the positive numbers 2^k-31561025 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 631196 + ... + 631245.

It is an arithmetic number, because the mean of its divisors is an integer number (6522617).

Almost surely, 2^31561025 is an apocalyptic number.

It is an amenable number.

31561025 is a deficient number, since it is larger than the sum of its proper divisors (7574677).

31561025 is a wasteful number, since it uses less digits than its factorization.

31561025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1262451 (or 1262446 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 31561025 is about 5617.9199887503. The cubic root of 31561025 is about 316.0217932147.

Adding to 31561025 its reverse (52016513), we get a palindrome (83577538).

The spelling of 31561025 in words is "thirty-one million, five hundred sixty-one thousand, twenty-five".