25644139920 has 480 divisors, whose sum is σ = 105379921920. Its totient is φ = 5671503360.

The previous prime is 25644139897. The next prime is 25644139949. The reversal of 25644139920 is 2993144652.

25644139920 is a `hidden beast` number, since 256 + 4 + 4 + 1 + 399 + 2 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 4215441 + ... + 4221519.

It is an arithmetic number, because the mean of its divisors is an integer number (219541504).

Almost surely, 2^25644139920 is an apocalyptic number.

25644139920 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 25644139920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52689960960).

25644139920 is an abundant number, since it is smaller than the sum of its proper divisors (79735782000).

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

25644139920 is a wasteful number, since it uses less digits than its factorization.

25644139920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6145 (or 6127 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The spelling of 25644139920 in words is "twenty-five billion, six hundred forty-four million, one hundred thirty-nine thousand, nine hundred twenty".