25216640 has 96 divisors (see below), whose sum is σ = 63810180. Its totient is φ = 9523200.

The previous prime is 25216613. The next prime is 25216657. The reversal of 25216640 is 4661252.

It can be written as a sum of positive squares in 2 ways, for example, as 22202944 + 3013696 = 4712^2 + 1736^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 615020 + ... + 615060.

Almost surely, 2^25216640 is an apocalyptic number.

25216640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 25216640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31905090).

25216640 is an abundant number, since it is smaller than the sum of its proper divisors (38593540).

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

25216640 is an equidigital number, since it uses as much as digits as its factorization.

25216640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 79 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 25216640 is about 5021.6172693665. The cubic root of 25216640 is about 293.2439580788.

Adding to 25216640 its reverse (4661252), we get a palindrome (29877892).

The spelling of 25216640 in words is "twenty-five million, two hundred sixteen thousand, six hundred forty".