667692661 has 4 divisors (see below), whose sum is σ = 702834400. Its totient is φ = 632550924.

The previous prime is 667692637. The next prime is 667692679. The reversal of 667692661 is 166296766.

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 a cyclic number.

It is not a de Polignac number, because 667692661 - 2¹⁹ = 667168373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667692611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17570841 + ... + 17570878.

It is an arithmetic number, because the mean of its divisors is an integer number (175708600).

Almost surely, 2^667692661 is an apocalyptic number.

It is an amenable number.

667692661 is a deficient number, since it is larger than the sum of its proper divisors (35141739).

667692661 is a wasteful number, since it uses less digits than its factorization.

667692661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35141738.

The product of its digits is 979776, while the sum is 49.

The square root of 667692661 is about 25839.7496311400. The cubic root of 667692661 is about 874.0283793392.

The spelling of 667692661 in words is "six hundred sixty-seven million, six hundred ninety-two thousand, six hundred sixty-one".