667116561 has 4 divisors (see below), whose sum is σ = 889488752. Its totient is φ = 444744372.

The previous prime is 667116529. The next prime is 667116563. The reversal of 667116561 is 165611766.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 667116561 - 2⁵ = 667116529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (667116563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111186091 + ... + 111186096.

It is an arithmetic number, because the mean of its divisors is an integer number (222372188).

Almost surely, 2^667116561 is an apocalyptic number.

It is an amenable number.

667116561 is a deficient number, since it is larger than the sum of its proper divisors (222372191).

667116561 is a wasteful number, since it uses less digits than its factorization.

667116561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222372190.

The product of its digits is 45360, while the sum is 39.

The square root of 667116561 is about 25828.5996716818. The cubic root of 667116561 is about 873.7769299990.

It can be divided in two parts, 6671 and 16561, that added together give a palindrome (23232).

The spelling of 667116561 in words is "six hundred sixty-seven million, one hundred sixteen thousand, five hundred sixty-one".