25390640 has 120 divisors (see below), whose sum is σ = 67485264. Its totient is φ = 8870400.

The previous prime is 25390637. The next prime is 25390649. The reversal of 25390640 is 4609352.

25390640 = 231² + 232² + ... + 445².

It is not an unprimeable number, because it can be changed into a prime (25390649) 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 23 ways as a sum of consecutive naturals, for example, 416210 + ... + 416270.

Almost surely, 2^25390640 is an apocalyptic number.

25390640 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 25390640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33742632).

25390640 is an abundant number, since it is smaller than the sum of its proper divisors (42094624).

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

25390640 is a wasteful number, since it uses less digits than its factorization.

25390640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 25390640 is about 5038.9125811032. The cubic root of 25390640 is about 293.9168938441.

Adding to 25390640 its reverse (4609352), we get a palindrome (29999992).

The spelling of 25390640 in words is "twenty-five million, three hundred ninety thousand, six hundred forty".