81080800777 has 4 divisors (see below), whose sum is σ = 81549476100. Its totient is φ = 80612125456.

The previous prime is 81080800769. The next prime is 81080800789. The reversal of 81080800777 is 77700808018.

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 70227120016 + 10853680761 = 265004^2 + 104181^2 .

It is a cyclic number.

It is not a de Polignac number, because 81080800777 - 2³ = 81080800769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81080800747) 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, 234337402 + ... + 234337747.

It is an arithmetic number, because the mean of its divisors is an integer number (20387369025).

Almost surely, 2^81080800777 is an apocalyptic number.

It is an amenable number.

81080800777 is a deficient number, since it is larger than the sum of its proper divisors (468675323).

81080800777 is a wasteful number, since it uses less digits than its factorization.

81080800777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468675322.

The product of its (nonzero) digits is 175616, while the sum is 46.

The spelling of 81080800777 in words is "eighty-one billion, eighty million, eight hundred thousand, seven hundred seventy-seven".