643800126 has 16 divisors (see below), whose sum is σ = 1329136128. Its totient is φ = 207677400.

The previous prime is 643800089. The next prime is 643800139. The reversal of 643800126 is 621008346.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 643800093 and 643800102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1730460 + ... + 1730831.

It is an arithmetic number, because the mean of its divisors is an integer number (83071008).

Almost surely, 2^643800126 is an apocalyptic number.

643800126 is an abundant number, since it is smaller than the sum of its proper divisors (685336002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643800126 is a wasteful number, since it uses less digits than its factorization.

643800126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3461327.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 643800126 is about 25373.2167058101. The cubic root of 643800126 is about 863.4761619096.

The spelling of 643800126 in words is "six hundred forty-three million, eight hundred thousand, one hundred twenty-six".