667724689 has 2 divisors, whose sum is σ = 667724690. Its totient is φ = 667724688.

The previous prime is 667724677. The next prime is 667724699. The reversal of 667724689 is 986427766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 609843025 + 57881664 = 24695^2 + 7608^2 .

It is a cyclic number.

It is not a de Polignac number, because 667724689 - 2¹¹ = 667722641 is a prime.

It is not a weakly prime, because it can be changed into another prime (667724699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333862344 + 333862345.

It is an arithmetic number, because the mean of its divisors is an integer number (333862345).

Almost surely, 2^667724689 is an apocalyptic number.

It is an amenable number.

667724689 is a deficient number, since it is larger than the sum of its proper divisors (1).

667724689 is an equidigital number, since it uses as much as digits as its factorization.

667724689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6096384, while the sum is 55.

The square root of 667724689 is about 25840.3693665551. The cubic root of 667724689 is about 874.0423542985.

The spelling of 667724689 in words is "six hundred sixty-seven million, seven hundred twenty-four thousand, six hundred eighty-nine".