81535865 has 8 divisors (see below), whose sum is σ = 98055360. Its totient is φ = 65087152.

The previous prime is 81535847. The next prime is 81535877. The reversal of 81535865 is 56853518.

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 81535865 - 2⁸ = 81535609 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15125 + ... + 19794.

It is an arithmetic number, because the mean of its divisors is an integer number (12256920).

Almost surely, 2^81535865 is an apocalyptic number.

It is an amenable number.

81535865 is a deficient number, since it is larger than the sum of its proper divisors (16519495).

81535865 is a wasteful number, since it uses less digits than its factorization.

81535865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35391.

The product of its digits is 144000, while the sum is 41.

The square root of 81535865 is about 9029.7212027836. The cubic root of 81535865 is about 433.6269118413.

The spelling of 81535865 in words is "eighty-one million, five hundred thirty-five thousand, eight hundred sixty-five".