666161669 has 2 divisors, whose sum is σ = 666161670. Its totient is φ = 666161668.

The previous prime is 666161623. The next prime is 666161681. The reversal of 666161669 is 966161666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 381733444 + 284428225 = 19538^2 + 16865^2 .

It is a cyclic number.

It is not a de Polignac number, because 666161669 - 2²⁴ = 649384453 is a prime.

It is a super-2 number, since 2×666161669² = 887542738489731122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666167669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333080834 + 333080835.

It is an arithmetic number, because the mean of its divisors is an integer number (333080835).

Almost surely, 2^666161669 is an apocalyptic number.

It is an amenable number.

666161669 is a deficient number, since it is larger than the sum of its proper divisors (1).

666161669 is an equidigital number, since it uses as much as digits as its factorization.

666161669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 419904, while the sum is 47.

The square root of 666161669 is about 25810.1078843154. The cubic root of 666161669 is about 873.3598309690.

The spelling of 666161669 in words is "six hundred sixty-six million, one hundred sixty-one thousand, six hundred sixty-nine".