25665221 has 8 divisors (see below), whose sum is σ = 26686464. Its totient is φ = 24662880.

The previous prime is 25665193. The next prime is 25665239. The reversal of 25665221 is 12256652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25665221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25665251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1925 + ... + 7418.

It is an arithmetic number, because the mean of its divisors is an integer number (3335808).

Almost surely, 2^25665221 is an apocalyptic number.

It is an amenable number.

25665221 is a deficient number, since it is larger than the sum of its proper divisors (1021243).

25665221 is an equidigital number, since it uses as much as digits as its factorization.

25665221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9451.

The product of its digits is 7200, while the sum is 29.

The square root of 25665221 is about 5066.0853723561. The cubic root of 25665221 is about 294.9725953667.

The spelling of 25665221 in words is "twenty-five million, six hundred sixty-five thousand, two hundred twenty-one".