643513305431 has 4 divisors (see below), whose sum is σ = 643523019864. Its totient is φ = 643503591000.

The previous prime is 643513305419. The next prime is 643513305439. The reversal of 643513305431 is 134503315346.

643513305431 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 643513305431 - 2⁶ = 643513305367 is a prime.

It is a super-2 number, since 2×643513305431² (a number of 24 digits) 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 (643513305439) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4757165 + ... + 4890566.

It is an arithmetic number, because the mean of its divisors is an integer number (160880754966).

Almost surely, 2^643513305431 is an apocalyptic number.

643513305431 is a deficient number, since it is larger than the sum of its proper divisors (9714433).

643513305431 is an equidigital number, since it uses as much as digits as its factorization.

643513305431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9714432.

The product of its (nonzero) digits is 194400, while the sum is 38.

The spelling of 643513305431 in words is "six hundred forty-three billion, five hundred thirteen million, three hundred five thousand, four hundred thirty-one".