81245695138608 has 640 divisors, whose sum is σ = 287706385612800. Its totient is φ = 19469188408320.

The previous prime is 81245695138589. The next prime is 81245695138661. The reversal of 81245695138608 is 80683159654218.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 5045368285 + ... + 5045384387.

It is an arithmetic number, because the mean of its divisors is an integer number (449541227520).

Almost surely, 2^{81245695138608} is an apocalyptic number.

81245695138608 is a gapful number since it is divisible by the number (88) 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 81245695138608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143853192806400).

81245695138608 is an abundant number, since it is smaller than the sum of its proper divisors (206460690474192).

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

81245695138608 is a wasteful number, since it uses less digits than its factorization.

81245695138608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18302 (or 18282 counting only the distinct ones).

The product of its (nonzero) digits is 99532800, while the sum is 66.

The spelling of 81245695138608 in words is "eighty-one trillion, two hundred forty-five billion, six hundred ninety-five million, one hundred thirty-eight thousand, six hundred eight".