25242221 has 4 divisors (see below), whose sum is σ = 25273500. Its totient is φ = 25210944.

The previous prime is 25242199. The next prime is 25242281. The reversal of 25242221 is 12224252.

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 8185321 + 17056900 = 2861^2 + 4130^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25242221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 25242193 and 25242202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25242281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14396 + ... + 16053.

It is an arithmetic number, because the mean of its divisors is an integer number (6318375).

Almost surely, 2^25242221 is an apocalyptic number.

It is an amenable number.

25242221 is a deficient number, since it is larger than the sum of its proper divisors (31279).

25242221 is an equidigital number, since it uses as much as digits as its factorization.

25242221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31278.

The product of its digits is 640, while the sum is 20.

The square root of 25242221 is about 5024.1637115046. The cubic root of 25242221 is about 293.3430849318.

Adding to 25242221 its reverse (12224252), we get a palindrome (37466473).

The spelling of 25242221 in words is "twenty-five million, two hundred forty-two thousand, two hundred twenty-one".