643236331 has 24 divisors (see below), whose sum is σ = 698683392. Its totient is φ = 590990400.

The previous prime is 643236311. The next prime is 643236337. The reversal of 643236331 is 133632346.

It is a happy number.

643236331 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 643236331 - 2⁹ = 643235819 is a prime.

It is a super-2 number, since 2×643236331² = 827505955036683122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643236293 and 643236302.

It is not an unprimeable number, because it can be changed into a prime (643236337) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4910136 + ... + 4910266.

It is an arithmetic number, because the mean of its divisors is an integer number (29111808).

Almost surely, 2^643236331 is an apocalyptic number.

643236331 is a deficient number, since it is larger than the sum of its proper divisors (55447061).

643236331 is a wasteful number, since it uses less digits than its factorization.

643236331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363 (or 322 counting only the distinct ones).

The product of its digits is 23328, while the sum is 31.

The square root of 643236331 is about 25362.1042305247. The cubic root of 643236331 is about 863.2240310070.

Adding to 643236331 its reverse (133632346), we get a palindrome (776868677).

The spelling of 643236331 in words is "six hundred forty-three million, two hundred thirty-six thousand, three hundred thirty-one".