81120577823 has 4 divisors (see below), whose sum is σ = 83737370688. Its totient is φ = 78503784960.

The previous prime is 81120577819. The next prime is 81120577847. The reversal of 81120577823 is 32877502118.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32877502118 = 2 ⋅16438751059.

It is not a de Polignac number, because 81120577823 - 2² = 81120577819 is a prime.

It is a super-3 number, since 3×81120577823³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81120577423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1308396386 + ... + 1308396447.

It is an arithmetic number, because the mean of its divisors is an integer number (20934342672).

Almost surely, 2^81120577823 is an apocalyptic number.

81120577823 is a deficient number, since it is larger than the sum of its proper divisors (2616792865).

81120577823 is a wasteful number, since it uses less digits than its factorization.

81120577823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2616792864.

The product of its (nonzero) digits is 188160, while the sum is 44.

The spelling of 81120577823 in words is "eighty-one billion, one hundred twenty million, five hundred seventy-seven thousand, eight hundred twenty-three".