25312561 has 4 divisors (see below), whose sum is σ = 25328500. Its totient is φ = 25296624.

The previous prime is 25312549. The next prime is 25312589. The reversal of 25312561 is 16521352.

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 23824161 + 1488400 = 4881^2 + 1220^2 .

It is a cyclic number.

It is not a de Polignac number, because 25312561 - 2¹⁷ = 25181489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25312501) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 5286 + ... + 8863.

It is an arithmetic number, because the mean of its divisors is an integer number (6332125).

Almost surely, 2^25312561 is an apocalyptic number.

It is an amenable number.

25312561 is a deficient number, since it is larger than the sum of its proper divisors (15939).

25312561 is a wasteful number, since it uses less digits than its factorization.

25312561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15938.

The product of its digits is 1800, while the sum is 25.

The square root of 25312561 is about 5031.1590115996. The cubic root of 25312561 is about 293.6153089462.

The spelling of 25312561 in words is "twenty-five million, three hundred twelve thousand, five hundred sixty-one".