25221231 has 18 divisors (see below), whose sum is σ = 42379272. Its totient is φ = 14411880.

The previous prime is 25221223. The next prime is 25221239. The reversal of 25221231 is 13212252.

It is an interprime number because it is at equal distance from previous prime (25221223) and next prime (25221239).

It is not a de Polignac number, because 25221231 - 2³ = 25221223 is a prime.

It is a super-2 number, since 2×25221231² = 1272220986310722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25221239) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 28155 + ... + 29036.

It is an arithmetic number, because the mean of its divisors is an integer number (2354404).

Almost surely, 2^25221231 is an apocalyptic number.

25221231 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

25221231 is a deficient number, since it is larger than the sum of its proper divisors (17158041).

25221231 is a wasteful number, since it uses less digits than its factorization.

25221231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57211 (or 57201 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 25221231 is about 5022.0743722092. The cubic root of 25221231 is about 293.2617532241.

Adding to 25221231 its reverse (13212252), we get a palindrome (38433483).

It can be divided in two parts, 25221 and 231, that added together give a palindrome (25452).

The spelling of 25221231 in words is "twenty-five million, two hundred twenty-one thousand, two hundred thirty-one".