667229021 has 2 divisors, whose sum is σ = 667229022. Its totient is φ = 667229020.

The previous prime is 667228993. The next prime is 667229063. The reversal of 667229021 is 120922766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 480223396 + 187005625 = 21914^2 + 13675^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667229021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667729021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333614510 + 333614511.

It is an arithmetic number, because the mean of its divisors is an integer number (333614511).

Almost surely, 2^667229021 is an apocalyptic number.

It is an amenable number.

667229021 is a deficient number, since it is larger than the sum of its proper divisors (1).

667229021 is an equidigital number, since it uses as much as digits as its factorization.

667229021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 667229021 is about 25830.7766240197. The cubic root of 667229021 is about 873.8260265828.

The spelling of 667229021 in words is "six hundred sixty-seven million, two hundred twenty-nine thousand, twenty-one".