643315331 has 2 divisors, whose sum is σ = 643315332. Its totient is φ = 643315330.

The previous prime is 643315301. The next prime is 643315369. The reversal of 643315331 is 133513346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643315331 - 2¹⁴ = 643298947 is a prime.

It is a super-2 number, since 2×643315331² = 827709230199279122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 643315294 and 643315303.

It is not a weakly prime, because it can be changed into another prime (643315301) 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, 321657665 + 321657666.

It is an arithmetic number, because the mean of its divisors is an integer number (321657666).

Almost surely, 2^643315331 is an apocalyptic number.

643315331 is a deficient number, since it is larger than the sum of its proper divisors (1).

643315331 is an equidigital number, since it uses as much as digits as its factorization.

643315331 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9720, while the sum is 29.

The square root of 643315331 is about 25363.6616244579. The cubic root of 643315331 is about 863.2593689295.

Adding to 643315331 its reverse (133513346), we get a palindrome (776828677).

The spelling of 643315331 in words is "six hundred forty-three million, three hundred fifteen thousand, three hundred thirty-one".