81593177849 has 8 divisors (see below), whose sum is σ = 86580187848. Its totient is φ = 76626991360.

The previous prime is 81593177843. The next prime is 81593177863. The reversal of 81593177849 is 94877139518.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1089330025 + 80503847824 = 33005^2 + 283732^2 .

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

It is not a de Polignac number, because 81593177849 - 2⁸ = 81593177593 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81593177791 and 81593177800.

It is not an unprimeable number, because it can be changed into a prime (81593177843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5197802 + ... + 5213475.

It is an arithmetic number, because the mean of its divisors is an integer number (10822523481).

Almost surely, 2^81593177849 is an apocalyptic number.

It is an amenable number.

81593177849 is a deficient number, since it is larger than the sum of its proper divisors (4987009999).

81593177849 is a wasteful number, since it uses less digits than its factorization.

81593177849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10411755.

The product of its digits is 15240960, while the sum is 62.

The spelling of 81593177849 in words is "eighty-one billion, five hundred ninety-three million, one hundred seventy-seven thousand, eight hundred forty-nine".