25553221 has 4 divisors (see below), whose sum is σ = 25598700. Its totient is φ = 25507744.

The previous prime is 25553219. The next prime is 25553237. The reversal of 25553221 is 12235552.

It is a happy number.

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 4264225 + 21288996 = 2065^2 + 4614^2 .

It is a cyclic number.

It is not a de Polignac number, because 25553221 - 2¹ = 25553219 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 (25553821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21886 + ... + 23023.

It is an arithmetic number, because the mean of its divisors is an integer number (6399675).

Almost surely, 2^25553221 is an apocalyptic number.

It is an amenable number.

25553221 is a deficient number, since it is larger than the sum of its proper divisors (45479).

25553221 is an equidigital number, since it uses as much as digits as its factorization.

25553221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45478.

The product of its digits is 3000, while the sum is 25.

The square root of 25553221 is about 5055.0193867086. The cubic root of 25553221 is about 294.5428944893.

Adding to 25553221 its reverse (12235552), we get a palindrome (37788773).

It can be divided in two parts, 2555 and 3221, that added together give a square (5776 = 76²).

The spelling of 25553221 in words is "twenty-five million, five hundred fifty-three thousand, two hundred twenty-one".