667989209 has 16 divisors (see below), whose sum is σ = 703572480. Its totient is φ = 633360000.

The previous prime is 667989197. The next prime is 667989281. The reversal of 667989209 is 902989766.

It is a cyclic number.

It is not a de Polignac number, because 667989209 - 2²⁴ = 651211993 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (667949209) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 952559 + ... + 953259.

It is an arithmetic number, because the mean of its divisors is an integer number (43973280).

Almost surely, 2^667989209 is an apocalyptic number.

It is an amenable number.

667989209 is a deficient number, since it is larger than the sum of its proper divisors (35583271).

667989209 is a wasteful number, since it uses less digits than its factorization.

667989209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1312.

The product of its (nonzero) digits is 2939328, while the sum is 56.

The square root of 667989209 is about 25845.4872076345. The cubic root of 667989209 is about 874.1577567310.

The spelling of 667989209 in words is "six hundred sixty-seven million, nine hundred eighty-nine thousand, two hundred nine".