667690509 has 8 divisors (see below), whose sum is σ = 898421920. Its totient is φ = 441043056.

The previous prime is 667690501. The next prime is 667690511. The reversal of 667690509 is 905096766.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 667690509 - 2³ = 667690501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667690501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1020607 + ... + 1021260.

It is an arithmetic number, because the mean of its divisors is an integer number (112302740).

Almost surely, 2^667690509 is an apocalyptic number.

It is an amenable number.

667690509 is a deficient number, since it is larger than the sum of its proper divisors (230731411).

667690509 is a wasteful number, since it uses less digits than its factorization.

667690509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2041979.

The product of its (nonzero) digits is 612360, while the sum is 48.

The square root of 667690509 is about 25839.7079898361. The cubic root of 667690509 is about 874.0274403287.

The spelling of 667690509 in words is "six hundred sixty-seven million, six hundred ninety thousand, five hundred nine".