81599349771 has 24 divisors (see below), whose sum is σ = 120854722560. Its totient is φ = 53025232176.

The previous prime is 81599349739. The next prime is 81599349773. The reversal of 81599349771 is 17794399518.

81599349771 is a `hidden beast` number, since 8 + 1 + 59 + 93 + 497 + 7 + 1 = 666.

It is not a de Polignac number, because 81599349771 - 2⁵ = 81599349739 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81599349699 and 81599349708.

It is not an unprimeable number, because it can be changed into a prime (81599349773) 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, 28011 + ... + 404948.

It is an arithmetic number, because the mean of its divisors is an integer number (5035613440).

Almost surely, 2^81599349771 is an apocalyptic number.

81599349771 is a deficient number, since it is larger than the sum of its proper divisors (39255372789).

81599349771 is a wasteful number, since it uses less digits than its factorization.

81599349771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433495 (or 433492 counting only the distinct ones).

The product of its digits is 17146080, while the sum is 63.

The spelling of 81599349771 in words is "eighty-one billion, five hundred ninety-nine million, three hundred forty-nine thousand, seven hundred seventy-one".