25400405520 has 640 divisors, whose sum is σ = 105501818880. Its totient is φ = 5494210560.

The previous prime is 25400405477. The next prime is 25400405573. The reversal of 25400405520 is 2550400452.

25400405520 is a `hidden beast` number, since 254 + 0 + 0 + 405 + 5 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 22029264 + ... + 22030416.

It is an arithmetic number, because the mean of its divisors is an integer number (164846592).

Almost surely, 2^25400405520 is an apocalyptic number.

25400405520 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 25400405520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52750909440).

25400405520 is an abundant number, since it is smaller than the sum of its proper divisors (80101413360).

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

25400405520 is a wasteful number, since it uses less digits than its factorization.

25400405520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260 (or 1248 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 27.

Adding to 25400405520 its reverse (2550400452), we get a palindrome (27950805972).

The spelling of 25400405520 in words is "twenty-five billion, four hundred million, four hundred five thousand, five hundred twenty".