25231521 has 24 divisors (see below), whose sum is σ = 40200960. Its totient is φ = 14025312.

The previous prime is 25231513. The next prime is 25231561. The reversal of 25231521 is 12513252.

It is not a de Polignac number, because 25231521 - 2³ = 25231513 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (25231561) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3120 + ... + 7758.

It is an arithmetic number, because the mean of its divisors is an integer number (1675040).

Almost surely, 2^25231521 is an apocalyptic number.

25231521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25231521 is a deficient number, since it is larger than the sum of its proper divisors (14969439).

25231521 is a wasteful number, since it uses less digits than its factorization.

25231521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4693 (or 4686 counting only the distinct ones).

The product of its digits is 600, while the sum is 21.

The square root of 25231521 is about 5023.0987447989. The cubic root of 25231521 is about 293.3016303834.

Adding to 25231521 its reverse (12513252), we get a palindrome (37744773).

It can be divided in two parts, 25231 and 521, that added together give a palindrome (25752).

The spelling of 25231521 in words is "twenty-five million, two hundred thirty-one thousand, five hundred twenty-one".