81105231077 has 4 divisors (see below), whose sum is σ = 87344095020. Its totient is φ = 74866367136.

The previous prime is 81105231061. The next prime is 81105231083. The reversal of 81105231077 is 77013250118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4016263876 + 77088967201 = 63374^2 + 277649^2 .

It is a cyclic number.

It is not a de Polignac number, because 81105231077 - 2⁴ = 81105231061 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81105231037) 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, 3119431952 + ... + 3119431977.

It is an arithmetic number, because the mean of its divisors is an integer number (21836023755).

Almost surely, 2^81105231077 is an apocalyptic number.

It is an amenable number.

81105231077 is a deficient number, since it is larger than the sum of its proper divisors (6238863943).

81105231077 is a wasteful number, since it uses less digits than its factorization.

81105231077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6238863942.

The product of its (nonzero) digits is 11760, while the sum is 35.

The spelling of 81105231077 in words is "eighty-one billion, one hundred five million, two hundred thirty-one thousand, seventy-seven".