643834 has 8 divisors (see below), whose sum is σ = 1016640. Its totient is φ = 304956.

The previous prime is 643781. The next prime is 643847. The reversal of 643834 is 438346.

643834 = 175² + 176² + ... + 193².

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

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, 8434 + ... + 8509.

It is an arithmetic number, because the mean of its divisors is an integer number (127080).

2⁶⁴³⁸³⁴ is an apocalyptic number.

643834 is a deficient number, since it is larger than the sum of its proper divisors (372806).

643834 is a wasteful number, since it uses less digits than its factorization.

643834 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16964.

The product of its digits is 6912, while the sum is 28.

The square root of 643834 is about 802.3926719506. The cubic root of 643834 is about 86.3491305781.

The spelling of 643834 in words is "six hundred forty-three thousand, eight hundred thirty-four".