81810560557 has 8 divisors (see below), whose sum is σ = 89262008640. Its totient is φ = 74361466560.

The previous prime is 81810560543. The next prime is 81810560617. The reversal of 81810560557 is 75506501818.

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

It is a cyclic number.

It is not a de Polignac number, because 81810560557 - 2¹¹ = 81810558509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81810560527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 515457 + ... + 655222.

It is an arithmetic number, because the mean of its divisors is an integer number (11157751080).

Almost surely, 2^81810560557 is an apocalyptic number.

It is an amenable number.

81810560557 is a deficient number, since it is larger than the sum of its proper divisors (7451448083).

81810560557 is a wasteful number, since it uses less digits than its factorization.

81810560557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1177043.

The product of its (nonzero) digits is 336000, while the sum is 46.

The spelling of 81810560557 in words is "eighty-one billion, eight hundred ten million, five hundred sixty thousand, five hundred fifty-seven".