81049318557 has 32 divisors (see below), whose sum is σ = 112379559936. Its totient is φ = 51903244800.

The previous prime is 81049318543. The next prime is 81049318579. The reversal of 81049318557 is 75581394018.

It is not a de Polignac number, because 81049318557 - 2¹⁵ = 81049285789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81049318657) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7315332 + ... + 7326402.

It is an arithmetic number, because the mean of its divisors is an integer number (3511861248).

Almost surely, 2^81049318557 is an apocalyptic number.

It is an amenable number.

81049318557 is a deficient number, since it is larger than the sum of its proper divisors (31330241379).

81049318557 is a wasteful number, since it uses less digits than its factorization.

81049318557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11681.

The product of its (nonzero) digits is 1209600, while the sum is 51.

The spelling of 81049318557 in words is "eighty-one billion, forty-nine million, three hundred eighteen thousand, five hundred fifty-seven".