643636126405 has 8 divisors (see below), whose sum is σ = 783241709184. Its totient is φ = 507656662800.

The previous prime is 643636126403. The next prime is 643636126417. The reversal of 643636126405 is 504621636346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 643636126405 - 2¹ = 643636126403 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643636126403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 906529401 + ... + 906530110.

It is an arithmetic number, because the mean of its divisors is an integer number (97905213648).

Almost surely, 2^643636126405 is an apocalyptic number.

It is an amenable number.

643636126405 is a deficient number, since it is larger than the sum of its proper divisors (139605582779).

643636126405 is a wasteful number, since it uses less digits than its factorization.

643636126405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1813059587.

The product of its (nonzero) digits is 1866240, while the sum is 46.

The spelling of 643636126405 in words is "six hundred forty-three billion, six hundred thirty-six million, one hundred twenty-six thousand, four hundred five".