81889508125 has 20 divisors (see below), whose sum is σ = 102456250380. Its totient is φ = 65430224000.

The previous prime is 81889508123. The next prime is 81889508149. The reversal of 81889508125 is 52180598818.

It can be written as a sum of positive squares in 10 ways, for example, as 22014843876 + 59874664249 = 148374^2 + 244693^2 .

It is not a de Polignac number, because 81889508125 - 2¹ = 81889508123 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81889508123) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 424647 + ... + 586603.

It is an arithmetic number, because the mean of its divisors is an integer number (5122812519).

Almost surely, 2^81889508125 is an apocalyptic number.

It is an amenable number.

81889508125 is a deficient number, since it is larger than the sum of its proper divisors (20566742255).

81889508125 is an equidigital number, since it uses as much as digits as its factorization.

81889508125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162786 (or 162771 counting only the distinct ones).

The product of its (nonzero) digits is 1843200, while the sum is 55.

The spelling of 81889508125 in words is "eighty-one billion, eight hundred eighty-nine million, five hundred eight thousand, one hundred twenty-five".