25216221 has 4 divisors (see below), whose sum is σ = 33621632. Its totient is φ = 16810812.

The previous prime is 25216201. The next prime is 25216223. The reversal of 25216221 is 12261252.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 25216221 - 2¹⁵ = 25183453 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 (25216223) 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, 4202701 + ... + 4202706.

It is an arithmetic number, because the mean of its divisors is an integer number (8405408).

Almost surely, 2^25216221 is an apocalyptic number.

It is an amenable number.

25216221 is a deficient number, since it is larger than the sum of its proper divisors (8405411).

25216221 is an equidigital number, since it uses as much as digits as its factorization.

25216221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8405410.

The product of its digits is 480, while the sum is 21.

The square root of 25216221 is about 5021.5755495661. The cubic root of 25216221 is about 293.2423338881.

Adding to 25216221 its reverse (12261252), we get a palindrome (37477473).

The spelling of 25216221 in words is "twenty-five million, two hundred sixteen thousand, two hundred twenty-one".