667940985 has 20 divisors (see below), whose sum is σ = 1197346788. Its totient is φ = 356234976.

The previous prime is 667940981. The next prime is 667940989. The reversal of 667940985 is 589049766.

It is an interprime number because it is at equal distance from previous prime (667940981) and next prime (667940989).

It can be written as a sum of positive squares in 2 ways, for example, as 385297641 + 282643344 = 19629^2 + 16812^2 .

It is not a de Polignac number, because 667940985 - 2² = 667940981 is a prime.

It is a super-2 number, since 2×667940985² = 892290318885540450, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (667940981) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 824214 + ... + 825023.

Almost surely, 2^667940985 is an apocalyptic number.

It is an amenable number.

667940985 is a deficient number, since it is larger than the sum of its proper divisors (529405803).

667940985 is a wasteful number, since it uses less digits than its factorization.

667940985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1649254 (or 1649245 counting only the distinct ones).

The product of its (nonzero) digits is 3265920, while the sum is 54.

The square root of 667940985 is about 25844.5542619717. The cubic root of 667940985 is about 874.1367202643.

The spelling of 667940985 in words is "six hundred sixty-seven million, nine hundred forty thousand, nine hundred eighty-five".