66800865 has 32 divisors (see below), whose sum is σ = 114923520. Its totient is φ = 33027264.

The previous prime is 66800863. The next prime is 66800869. The reversal of 66800865 is 56800866.

It is not a de Polignac number, because 66800865 - 2¹ = 66800863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66800863) 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, 10902 + ... + 15888.

It is an arithmetic number, because the mean of its divisors is an integer number (3591360).

Almost surely, 2^66800865 is an apocalyptic number.

It is an amenable number.

66800865 is a deficient number, since it is larger than the sum of its proper divisors (48122655).

66800865 is a wasteful number, since it uses less digits than its factorization.

66800865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5061.

The product of its (nonzero) digits is 69120, while the sum is 39.

The square root of 66800865 is about 8173.1796138345. The cubic root of 66800865 is about 405.7520244731.

Subtracting from 66800865 its reverse (56800866), we obtain a palindrome (9999999).

The spelling of 66800865 in words is "sixty-six million, eight hundred thousand, eight hundred sixty-five".