667874021 has 4 divisors (see below), whose sum is σ = 668291232. Its totient is φ = 667456812.

The previous prime is 667874017. The next prime is 667874027. The reversal of 667874021 is 120478766.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 667874021 - 2² = 667874017 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 667874021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667874027) 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 3 ways as a sum of consecutive naturals, for example, 206195 + ... + 209408.

It is an arithmetic number, because the mean of its divisors is an integer number (167072808).

Almost surely, 2^667874021 is an apocalyptic number.

It is an amenable number.

667874021 is a deficient number, since it is larger than the sum of its proper divisors (417211).

667874021 is a wasteful number, since it uses less digits than its factorization.

667874021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417210.

The product of its (nonzero) digits is 112896, while the sum is 41.

The square root of 667874021 is about 25843.2587147983. The cubic root of 667874021 is about 874.1075072805.

The spelling of 667874021 in words is "six hundred sixty-seven million, eight hundred seventy-four thousand, twenty-one".