643130331 has 4 divisors (see below), whose sum is σ = 857507112. Its totient is φ = 428753552.

The previous prime is 643130329. The next prime is 643130357. The reversal of 643130331 is 133031346.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643130331 - 2¹ = 643130329 is a prime.

It is a super-2 number, since 2×643130331² = 827233245304339122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (643132331) 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 in 3 ways as a sum of consecutive naturals, for example, 107188386 + ... + 107188391.

It is an arithmetic number, because the mean of its divisors is an integer number (214376778).

Almost surely, 2^643130331 is an apocalyptic number.

643130331 is a deficient number, since it is larger than the sum of its proper divisors (214376781).

643130331 is a wasteful number, since it uses less digits than its factorization.

643130331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214376780.

The product of its (nonzero) digits is 1944, while the sum is 24.

The square root of 643130331 is about 25360.0144124565. The cubic root of 643130331 is about 863.1766110207.

Adding to 643130331 its reverse (133031346), we get a palindrome (776161677).

The spelling of 643130331 in words is "six hundred forty-three million, one hundred thirty thousand, three hundred thirty-one".