670666021 has 2 divisors, whose sum is σ = 670666022. Its totient is φ = 670666020.

The previous prime is 670666001. The next prime is 670666037. The reversal of 670666021 is 120666076.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 494573121 + 176092900 = 22239^2 + 13270^2 .

It is a cyclic number.

It is not a de Polignac number, because 670666021 - 2¹⁹ = 670141733 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (670666001) 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, 335333010 + 335333011.

It is an arithmetic number, because the mean of its divisors is an integer number (335333011).

Almost surely, 2^670666021 is an apocalyptic number.

It is an amenable number.

670666021 is a deficient number, since it is larger than the sum of its proper divisors (1).

670666021 is an equidigital number, since it uses as much as digits as its factorization.

670666021 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 34.

The square root of 670666021 is about 25897.2203334644. The cubic root of 670666021 is about 875.3238620468.

Subtracting from 670666021 its reverse (120666076), we obtain a palindrome (549999945).

It can be divided in two parts, 6706 and 66021, that added together give a palindrome (72727).

The spelling of 670666021 in words is "six hundred seventy million, six hundred sixty-six thousand, twenty-one".