643339831 has 16 divisors (see below), whose sum is σ = 693203904. Its totient is φ = 595482624.

The previous prime is 643339819. The next prime is 643339841. The reversal of 643339831 is 138933346.

643339831 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 643339831 - 2¹⁷ = 643208759 is a prime.

It is a super-2 number, since 2×643339831² = 827772276302217122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643339841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 162285 + ... + 166201.

It is an arithmetic number, because the mean of its divisors is an integer number (43325244).

Almost surely, 2^643339831 is an apocalyptic number.

643339831 is a deficient number, since it is larger than the sum of its proper divisors (49864073).

643339831 is a wasteful number, since it uses less digits than its factorization.

643339831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4170.

The product of its digits is 139968, while the sum is 40.

The square root of 643339831 is about 25364.1445942890. The cubic root of 643339831 is about 863.2703275709.

It can be divided in two parts, 6433 and 39831, that added together give a palindrome (46264).

The spelling of 643339831 in words is "six hundred forty-three million, three hundred thirty-nine thousand, eight hundred thirty-one".