643545431131 has 4 divisors (see below), whose sum is σ = 658511603992. Its totient is φ = 628579258272.

The previous prime is 643545431033. The next prime is 643545431153. The reversal of 643545431131 is 131134545346.

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 643545431131 - 2⁷ = 643545431003 is a prime.

It is a super-2 number, since 2×643545431131² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643545431171) 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, 7483086366 + ... + 7483086451.

It is an arithmetic number, because the mean of its divisors is an integer number (164627900998).

Almost surely, 2^643545431131 is an apocalyptic number.

643545431131 is a deficient number, since it is larger than the sum of its proper divisors (14966172861).

643545431131 is a wasteful number, since it uses less digits than its factorization.

643545431131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14966172860.

The product of its digits is 259200, while the sum is 40.

Adding to 643545431131 its reverse (131134545346), we get a palindrome (774679976477).

The spelling of 643545431131 in words is "six hundred forty-three billion, five hundred forty-five million, four hundred thirty-one thousand, one hundred thirty-one".