643511673131 has 4 divisors (see below), whose sum is σ = 671490441552. Its totient is φ = 615532904712.

The previous prime is 643511673067. The next prime is 643511673173. The reversal of 643511673131 is 131376115346.

It is a happy number.

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 643511673131 - 2⁶ = 643511673067 is a prime.

It is a super-2 number, since 2×643511673131² (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 (643511672131) 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, 13989384176 + ... + 13989384221.

It is an arithmetic number, because the mean of its divisors is an integer number (167872610388).

Almost surely, 2^643511673131 is an apocalyptic number.

643511673131 is a deficient number, since it is larger than the sum of its proper divisors (27978768421).

643511673131 is a wasteful number, since it uses less digits than its factorization.

643511673131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27978768420.

The product of its digits is 136080, while the sum is 41.

Adding to 643511673131 its reverse (131376115346), we get a palindrome (774887788477).

The spelling of 643511673131 in words is "six hundred forty-three billion, five hundred eleven million, six hundred seventy-three thousand, one hundred thirty-one".