865665081 has 12 divisors (see below), whose sum is σ = 1253111808. Its totient is φ = 575860824.

The previous prime is 865665067. The next prime is 865665107. The reversal of 865665081 is 180566568.

865665081 is a `hidden beast` number, since 8 + 6 + 566 + 5 + 0 + 81 = 666.

It is not a de Polignac number, because 865665081 - 2¹³ = 865656889 is a prime.

It is a super-2 number, since 2×865665081² = 1498752064925473122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (865665781) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 99705 + ... + 108038.

It is an arithmetic number, because the mean of its divisors is an integer number (104425984).

Almost surely, 2^865665081 is an apocalyptic number.

It is an amenable number.

865665081 is a deficient number, since it is larger than the sum of its proper divisors (387446727).

865665081 is a wasteful number, since it uses less digits than its factorization.

865665081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208212 (or 208209 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The square root of 865665081 is about 29422.1868833709. The cubic root of 865665081 is about 953.0520791454.

It can be divided in two parts, 8656 and 65081, that added together give a palindrome (73737).

The spelling of 865665081 in words is "eight hundred sixty-five million, six hundred sixty-five thousand, eighty-one".