667475021 has 2 divisors, whose sum is σ = 667475022. Its totient is φ = 667475020.

The previous prime is 667475009. The next prime is 667475093. The reversal of 667475021 is 120574766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 665072521 + 2402500 = 25789^2 + 1550^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667475021 is a prime.

It is a super-3 number, since 3×667475021³ (a number of 27 digits) contains 333 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667475621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333737510 + 333737511.

It is an arithmetic number, because the mean of its divisors is an integer number (333737511).

Almost surely, 2^667475021 is an apocalyptic number.

It is an amenable number.

667475021 is a deficient number, since it is larger than the sum of its proper divisors (1).

667475021 is an equidigital number, since it uses as much as digits as its factorization.

667475021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 70560, while the sum is 38.

The square root of 667475021 is about 25835.5379467895. The cubic root of 667475021 is about 873.9334034021.

The spelling of 667475021 in words is "six hundred sixty-seven million, four hundred seventy-five thousand, twenty-one".