81619128375 has 24 divisors (see below), whose sum is σ = 135823436112. Its totient is φ = 43527251200.

The previous prime is 81619128359. The next prime is 81619128377. The reversal of 81619128375 is 57382191618.

It is not a de Polignac number, because 81619128375 - 2⁴ = 81619128359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81619128377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5524999 + ... + 5539751.

It is an arithmetic number, because the mean of its divisors is an integer number (5659309838).

Almost surely, 2^81619128375 is an apocalyptic number.

81619128375 is a deficient number, since it is larger than the sum of its proper divisors (54204307737).

81619128375 is an frugal number, since it uses more digits than its factorization.

81619128375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29524 (or 14761 counting only the distinct ones).

The product of its digits is 725760, while the sum is 51.

The spelling of 81619128375 in words is "eighty-one billion, six hundred nineteen million, one hundred twenty-eight thousand, three hundred seventy-five".