25644647340081 has 48 divisors (see below), whose sum is σ = 46236710782080. Its totient is φ = 13306276719360.

The previous prime is 25644647339921. The next prime is 25644647340101. The reversal of 25644647340081 is 18004374644652.

25644647340081 is a `hidden beast` number, since 2 + 5 + 64 + 464 + 7 + 3 + 40 + 0 + 81 = 666.

It is not a de Polignac number, because 25644647340081 - 2²¹ = 25644645242929 is a prime.

It is a super-2 number, since 2×25644647340081² (a number of 28 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (25644647340181) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 21100116 + ... + 22282373.

It is an arithmetic number, because the mean of its divisors is an integer number (963264807960).

Almost surely, 2^{25644647340081} is an apocalyptic number.

25644647340081 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25644647340081 is a deficient number, since it is larger than the sum of its proper divisors (20592063441999).

25644647340081 is a wasteful number, since it uses less digits than its factorization.

25644647340081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43383366 (or 43383363 counting only the distinct ones).

The product of its (nonzero) digits is 15482880, while the sum is 54.

The spelling of 25644647340081 in words is "twenty-five trillion, six hundred forty-four billion, six hundred forty-seven million, three hundred forty thousand, eighty-one".