81088077569 has 4 divisors (see below), whose sum is σ = 81130467396. Its totient is φ = 81045687744.

The previous prime is 81088077563. The next prime is 81088077599. The reversal of 81088077569 is 96577088018.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96577088018 = 2 ⋅48288544009.

It can be written as a sum of positive squares in 2 ways, for example, as 37128665344 + 43959412225 = 192688^2 + 209665^2 .

It is a cyclic number.

It is not a de Polignac number, because 81088077569 - 2²⁴ = 81071300353 is a prime.

It is a super-2 number, since 2×81088077569² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81088077563) 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, 21192044 + ... + 21195869.

It is an arithmetic number, because the mean of its divisors is an integer number (20282616849).

Almost surely, 2^81088077569 is an apocalyptic number.

It is an amenable number.

81088077569 is a deficient number, since it is larger than the sum of its proper divisors (42389827).

81088077569 is a wasteful number, since it uses less digits than its factorization.

81088077569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42389826.

The product of its (nonzero) digits is 6773760, while the sum is 59.

The spelling of 81088077569 in words is "eighty-one billion, eighty-eight million, seventy-seven thousand, five hundred sixty-nine".