81191376523 has 8 divisors (see below), whose sum is σ = 81491437296. Its totient is φ = 80891395200.

The previous prime is 81191376503. The next prime is 81191376547. The reversal of 81191376523 is 32567319118.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81191376523 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81191376503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2716740 + ... + 2746462.

It is an arithmetic number, because the mean of its divisors is an integer number (10186429662).

Almost surely, 2^81191376523 is an apocalyptic number.

81191376523 is a deficient number, since it is larger than the sum of its proper divisors (300060773).

81191376523 is a wasteful number, since it uses less digits than its factorization.

81191376523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39725.

The product of its digits is 272160, while the sum is 46.

The spelling of 81191376523 in words is "eighty-one billion, one hundred ninety-one million, three hundred seventy-six thousand, five hundred twenty-three".