643958390 has 16 divisors (see below), whose sum is σ = 1162239408. Its totient is φ = 256891296.

The previous prime is 643958389. The next prime is 643958401. The reversal of 643958390 is 93859346.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82592 + ... + 90051.

It is an arithmetic number, because the mean of its divisors is an integer number (72639963).

Almost surely, 2^643958390 is an apocalyptic number.

643958390 is a deficient number, since it is larger than the sum of its proper divisors (518281018).

643958390 is a wasteful number, since it uses less digits than its factorization.

643958390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173023.

The product of its (nonzero) digits is 699840, while the sum is 47.

The square root of 643958390 is about 25376.3352358058. The cubic root of 643958390 is about 863.5469116082.

The spelling of 643958390 in words is "six hundred forty-three million, nine hundred fifty-eight thousand, three hundred ninety".