25815268440 has 384 divisors, whose sum is σ = 93140087040. Its totient is φ = 6160831488.

The previous prime is 25815268429. The next prime is 25815268447. The reversal of 25815268440 is 4486251852.

25815268440 is a `hidden beast` number, since 2 + 5 + 8 + 1 + 526 + 84 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25815268447) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 32801727 + ... + 32802513.

It is an arithmetic number, because the mean of its divisors is an integer number (242552310).

Almost surely, 2^25815268440 is an apocalyptic number.

25815268440 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 25815268440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46570043520).

25815268440 is an abundant number, since it is smaller than the sum of its proper divisors (67324818600).

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

25815268440 is a wasteful number, since it uses less digits than its factorization.

25815268440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1023 (or 1016 counting only the distinct ones).

The product of its (nonzero) digits is 614400, while the sum is 45.

The spelling of 25815268440 in words is "twenty-five billion, eight hundred fifteen million, two hundred sixty-eight thousand, four hundred forty".