81804545577 has 12 divisors (see below), whose sum is σ = 118914748420. Its totient is φ = 54188997408.

The previous prime is 81804545551. The next prime is 81804545591. The reversal of 81804545577 is 77554540818.

81804545577 is a `hidden beast` number, since 8 + 1 + 80 + 4 + 5 + 4 + 557 + 7 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 27815234841 + 53989310736 = 166779^2 + 232356^2 .

It is not a de Polignac number, because 81804545577 - 2³² = 77509578281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81804545077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28945702 + ... + 28948527.

Almost surely, 2^81804545577 is an apocalyptic number.

It is an amenable number.

81804545577 is a deficient number, since it is larger than the sum of its proper divisors (37110202843).

81804545577 is a wasteful number, since it uses less digits than its factorization.

81804545577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57894392 (or 57894389 counting only the distinct ones).

The product of its (nonzero) digits is 6272000, while the sum is 54.

The spelling of 81804545577 in words is "eighty-one billion, eight hundred four million, five hundred forty-five thousand, five hundred seventy-seven".