25431521 has 16 divisors (see below), whose sum is σ = 27412560. Its totient is φ = 23546880.

The previous prime is 25431517. The next prime is 25431569. The reversal of 25431521 is 12513452.

It can be written as a sum of positive squares in 8 ways, for example, as 40000 + 25391521 = 200^2 + 5039^2 .

It is not a de Polignac number, because 25431521 - 2² = 25431517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25431221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86651 + ... + 86943.

It is an arithmetic number, because the mean of its divisors is an integer number (1713285).

Almost surely, 2^25431521 is an apocalyptic number.

It is an amenable number.

25431521 is a deficient number, since it is larger than the sum of its proper divisors (1981039).

25431521 is a wasteful number, since it uses less digits than its factorization.

25431521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436.

The product of its digits is 1200, while the sum is 23.

The square root of 25431521 is about 5042.9674795699. The cubic root of 25431521 is about 294.0745526453.

Adding to 25431521 its reverse (12513452), we get a palindrome (37944973).

It can be divided in two parts, 25431 and 521, that added together give a palindrome (25952).

The spelling of 25431521 in words is "twenty-five million, four hundred thirty-one thousand, five hundred twenty-one".