66800161 has 4 divisors (see below), whose sum is σ = 66816900. Its totient is φ = 66783424.

The previous prime is 66800141. The next prime is 66800177. The reversal of 66800161 is 16100866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 61324561 + 5475600 = 7831^2 + 2340^2 .

It is a cyclic number.

It is not a de Polignac number, because 66800161 - 2⁷ = 66800033 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66800131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1485 + ... + 11653.

It is an arithmetic number, because the mean of its divisors is an integer number (16704225).

Almost surely, 2^66800161 is an apocalyptic number.

It is an amenable number.

66800161 is a deficient number, since it is larger than the sum of its proper divisors (16739).

66800161 is a wasteful number, since it uses less digits than its factorization.

66800161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16738.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 66800161 is about 8173.1365460269. The cubic root of 66800161 is about 405.7505990903.

The spelling of 66800161 in words is "sixty-six million, eight hundred thousand, one hundred sixty-one".