6664381 has 2 divisors, whose sum is σ = 6664382. Its totient is φ = 6664380.

The previous prime is 6664351. The next prime is 6664387. The reversal of 6664381 is 1834666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6125625 + 538756 = 2475^2 + 734^2 .

It is a cyclic number.

It is not a de Polignac number, because 6664381 - 2⁹ = 6663869 is a prime.

It is a super-2 number, since 2×6664381² = 88827948226322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6664387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3332190 + 3332191.

It is an arithmetic number, because the mean of its divisors is an integer number (3332191).

Almost surely, 2^6664381 is an apocalyptic number.

It is an amenable number.

6664381 is a deficient number, since it is larger than the sum of its proper divisors (1).

6664381 is an equidigital number, since it uses as much as digits as its factorization.

6664381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 34.

The square root of 6664381 is about 2581.5462420805. The cubic root of 6664381 is about 188.1856943708.

The spelling of 6664381 in words is "six million, six hundred sixty-four thousand, three hundred eighty-one".