81857570135 has 32 divisors (see below), whose sum is σ = 112827237120. Its totient is φ = 56385331200.

The previous prime is 81857570117. The next prime is 81857570143. The reversal of 81857570135 is 53107575818.

It is not a de Polignac number, because 81857570135 - 2¹⁰ = 81857569111 is a prime.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5806295 + ... + 5820375.

It is an arithmetic number, because the mean of its divisors is an integer number (3525851160).

Almost surely, 2^81857570135 is an apocalyptic number.

81857570135 is a deficient number, since it is larger than the sum of its proper divisors (30969666985).

81857570135 is a wasteful number, since it uses less digits than its factorization.

81857570135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19679.

The product of its (nonzero) digits is 1176000, while the sum is 50.

The spelling of 81857570135 in words is "eighty-one billion, eight hundred fifty-seven million, five hundred seventy thousand, one hundred thirty-five".