643071406631 has 4 divisors (see below), whose sum is σ = 643080778512. Its totient is φ = 643062034752.

The previous prime is 643071406603. The next prime is 643071406657. The reversal of 643071406631 is 136604170346.

643071406631 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 643071406631 - 2¹⁸ = 643071144487 is a prime.

It is a super-2 number, since 2×643071406631² (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 (643071406031) 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, 4582250 + ... + 4720503.

It is an arithmetic number, because the mean of its divisors is an integer number (160770194628).

Almost surely, 2^643071406631 is an apocalyptic number.

643071406631 is a deficient number, since it is larger than the sum of its proper divisors (9371881).

643071406631 is an equidigital number, since it uses as much as digits as its factorization.

643071406631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9371880.

The product of its (nonzero) digits is 217728, while the sum is 41.

Adding to 643071406631 its reverse (136604170346), we get a palindrome (779675576977).

The spelling of 643071406631 in words is "six hundred forty-three billion, seventy-one million, four hundred six thousand, six hundred thirty-one".