6664720331 has 2 divisors, whose sum is σ = 6664720332. Its totient is φ = 6664720330.

The previous prime is 6664720319. The next prime is 6664720393. The reversal of 6664720331 is 1330274666.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6664720331 is a prime.

It is a super-2 number, since 2×6664720331² = 88836994180889499122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6664720631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3332360165 + 3332360166.

It is an arithmetic number, because the mean of its divisors is an integer number (3332360166).

Almost surely, 2^6664720331 is an apocalyptic number.

6664720331 is a deficient number, since it is larger than the sum of its proper divisors (1).

6664720331 is an equidigital number, since it uses as much as digits as its factorization.

6664720331 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108864, while the sum is 38.

The square root of 6664720331 is about 81637.7383995907. The cubic root of 6664720331 is about 1881.8888827362. Note that the first 5 decimals are identical.

Adding to 6664720331 its reverse (1330274666), we get a palindrome (7994994997).

The spelling of 6664720331 in words is "six billion, six hundred sixty-four million, seven hundred twenty thousand, three hundred thirty-one".