667661173 has 2 divisors, whose sum is σ = 667661174. Its totient is φ = 667661172.

The previous prime is 667661107. The next prime is 667661177. The reversal of 667661173 is 371166766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 607474609 + 60186564 = 24647^2 + 7758^2 .

It is a cyclic number.

It is not a de Polignac number, because 667661173 - 2¹³ = 667652981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667661177) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333830586 + 333830587.

It is an arithmetic number, because the mean of its divisors is an integer number (333830587).

Almost surely, 2^667661173 is an apocalyptic number.

It is an amenable number.

667661173 is a deficient number, since it is larger than the sum of its proper divisors (1).

667661173 is an equidigital number, since it uses as much as digits as its factorization.

667661173 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 190512, while the sum is 43.

The square root of 667661173 is about 25839.1403301271. The cubic root of 667661173 is about 874.0146395654.

The spelling of 667661173 in words is "six hundred sixty-seven million, six hundred sixty-one thousand, one hundred seventy-three".