667818987 has 16 divisors (see below), whose sum is σ = 977340288. Its totient is φ = 402252480.

The previous prime is 667818979. The next prime is 667819001. The reversal of 667818987 is 789818766.

It is not a de Polignac number, because 667818987 - 2³ = 667818979 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 667818987.

It is not an unprimeable number, because it can be changed into a prime (667818287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 56698 + ... + 67455.

It is an arithmetic number, because the mean of its divisors is an integer number (61083768).

Almost surely, 2^667818987 is an apocalyptic number.

667818987 is a deficient number, since it is larger than the sum of its proper divisors (309521301).

667818987 is a wasteful number, since it uses less digits than its factorization.

667818987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124330.

The product of its digits is 8128512, while the sum is 60.

The square root of 667818987 is about 25842.1939277609. The cubic root of 667818987 is about 874.0834972864.

The spelling of 667818987 in words is "six hundred sixty-seven million, eight hundred eighteen thousand, nine hundred eighty-seven".