25661216 has 48 divisors (see below), whose sum is σ = 58322880. Its totient is φ = 10886400.

The previous prime is 25661189. The next prime is 25661221. The reversal of 25661216 is 61216652.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 23891 + ... + 24941.

It is an arithmetic number, because the mean of its divisors is an integer number (1215060).

Almost surely, 2^25661216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25661216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29161440).

25661216 is an abundant number, since it is smaller than the sum of its proper divisors (32661664).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

25661216 is a wasteful number, since it uses less digits than its factorization.

25661216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1177 (or 1169 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 25661216 is about 5065.6900813216. The cubic root of 25661216 is about 294.9572512986.

Adding to 25661216 its reverse (61216652), we get a palindrome (86877868).

The spelling of 25661216 in words is "twenty-five million, six hundred sixty-one thousand, two hundred sixteen".