81845577261 has 24 divisors (see below), whose sum is σ = 135423684864. Its totient is φ = 46660373280.

The previous prime is 81845577181. The next prime is 81845577263. The reversal of 81845577261 is 16277554818.

81845577261 is a `hidden beast` number, since 8 + 1 + 8 + 4 + 5 + 577 + 2 + 61 = 666.

It is not a de Polignac number, because 81845577261 - 2⁹ = 81845576749 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81845577198 and 81845577207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81845577263) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1479966 + ... + 1534271.

It is an arithmetic number, because the mean of its divisors is an integer number (5642653536).

Almost surely, 2^81845577261 is an apocalyptic number.

It is an amenable number.

81845577261 is a deficient number, since it is larger than the sum of its proper divisors (53578107603).

81845577261 is a wasteful number, since it uses less digits than its factorization.

81845577261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3014681 (or 3014678 counting only the distinct ones).

The product of its digits is 3763200, while the sum is 54.

The spelling of 81845577261 in words is "eighty-one billion, eight hundred forty-five million, five hundred seventy-seven thousand, two hundred sixty-one".