25531221 has 16 divisors (see below), whose sum is σ = 35493824. Its totient is φ = 16308864.

The previous prime is 25531217. The next prime is 25531241. The reversal of 25531221 is 12213552.

25531221 = 584² + 585² + ... + 650².

It is not a de Polignac number, because 25531221 - 2² = 25531217 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25531201) 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, 5721 + ... + 9153.

It is an arithmetic number, because the mean of its divisors is an integer number (2218364).

Almost surely, 2^25531221 is an apocalyptic number.

It is an amenable number.

25531221 is a deficient number, since it is larger than the sum of its proper divisors (9962603).

25531221 is a wasteful number, since it uses less digits than its factorization.

25531221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3540.

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

The square root of 25531221 is about 5052.8428631811. The cubic root of 25531221 is about 294.4583414930.

Adding to 25531221 its reverse (12213552), we get a palindrome (37744773).

It can be divided in two parts, 25531 and 221, that added together give a palindrome (25752).

The spelling of 25531221 in words is "twenty-five million, five hundred thirty-one thousand, two hundred twenty-one".