25665237840 has 160 divisors (see below), whose sum is σ = 86866761600. Its totient is φ = 6216744960.

The previous prime is 25665237821. The next prime is 25665237847. The reversal of 25665237840 is 4873256652.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 25665237840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25665237847) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3927696 + ... + 3934224.

It is an arithmetic number, because the mean of its divisors is an integer number (542917260).

Almost surely, 2^25665237840 is an apocalyptic number.

25665237840 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 25665237840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43433380800).

25665237840 is an abundant number, since it is smaller than the sum of its proper divisors (61201523760).

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

25665237840 is a wasteful number, since it uses less digits than its factorization.

25665237840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8045 (or 8039 counting only the distinct ones).

The product of its (nonzero) digits is 2419200, while the sum is 48.

It can be divided in two parts, 256652 and 37840, that added together give a palindrome (294492).

The spelling of 25665237840 in words is "twenty-five billion, six hundred sixty-five million, two hundred thirty-seven thousand, eight hundred forty".