25730640 has 120 divisors (see below), whose sum is σ = 93093000. Its totient is φ = 6331392.

The previous prime is 25730633. The next prime is 25730647. The reversal of 25730640 is 4603752.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (25730633) and next prime (25730647).

It can be written as a sum of positive squares in 4 ways, for example, as 207936 + 25522704 = 456^2 + 5052^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25730647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7986 + ... + 10734.

It is an arithmetic number, because the mean of its divisors is an integer number (775775).

Almost surely, 2^25730640 is an apocalyptic number.

25730640 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 25730640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46546500).

25730640 is an abundant number, since it is smaller than the sum of its proper divisors (67362360).

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

25730640 is a wasteful number, since it uses less digits than its factorization.

25730640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2781 (or 2772 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 27.

The square root of 25730640 is about 5072.5378263745. The cubic root of 25730640 is about 295.2230047950.

The spelling of 25730640 in words is "twenty-five million, seven hundred thirty thousand, six hundred forty".