643890790 has 8 divisors (see below), whose sum is σ = 1159003440. Its totient is φ = 257556312.

The previous prime is 643890749. The next prime is 643890809. The reversal of 643890790 is 97098346.

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

It is a self number, because there is not a number n which added to its sum of digits gives 643890790.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32194530 + ... + 32194549.

It is an arithmetic number, because the mean of its divisors is an integer number (144875430).

Almost surely, 2^643890790 is an apocalyptic number.

643890790 is a deficient number, since it is larger than the sum of its proper divisors (515112650).

643890790 is a wasteful number, since it uses less digits than its factorization.

643890790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64389086.

The product of its (nonzero) digits is 326592, while the sum is 46.

The square root of 643890790 is about 25375.0032512313. The cubic root of 643890790 is about 863.5166933959.

It can be divided in two parts, 643890 and 790, that added together give a triangular number (644680 = T₁₁₃₅).

The spelling of 643890790 in words is "six hundred forty-three million, eight hundred ninety thousand, seven hundred ninety".