81138675259 has 4 divisors (see below), whose sum is σ = 81139245880. Its totient is φ = 81138104640.

The previous prime is 81138675227. The next prime is 81138675307. The reversal of 81138675259 is 95257683118.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 81138675259 - 2⁵ = 81138675227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81138675209) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 118324 + ... + 419854.

It is an arithmetic number, because the mean of its divisors is an integer number (20284811470).

Almost surely, 2^81138675259 is an apocalyptic number.

81138675259 is a deficient number, since it is larger than the sum of its proper divisors (570621).

81138675259 is a wasteful number, since it uses less digits than its factorization.

81138675259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570620.

The product of its digits is 3628800, while the sum is 55.

The spelling of 81138675259 in words is "eighty-one billion, one hundred thirty-eight million, six hundred seventy-five thousand, two hundred fifty-nine".