25621221 has 12 divisors (see below), whose sum is σ = 35303136. Its totient is φ = 16527960.

The previous prime is 25621199. The next prime is 25621237. The reversal of 25621221 is 12212652.

It is a happy number.

It is not a de Polignac number, because 25621221 - 2⁹ = 25620709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25625221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1561 + ... + 7326.

It is an arithmetic number, because the mean of its divisors is an integer number (2941928).

Almost surely, 2^25621221 is an apocalyptic number.

It is an amenable number.

25621221 is a deficient number, since it is larger than the sum of its proper divisors (9681915).

25621221 is an equidigital number, since it uses as much as digits as its factorization.

25621221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8952 (or 8921 counting only the distinct ones).

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

The square root of 25621221 is about 5061.7409060520. The cubic root of 25621221 is about 294.8039336833.

Adding to 25621221 its reverse (12212652), we get a palindrome (37833873).

The spelling of 25621221 in words is "twenty-five million, six hundred twenty-one thousand, two hundred twenty-one".