643802 has 4 divisors (see below), whose sum is σ = 965706. Its totient is φ = 321900.

The previous prime is 643781. The next prime is 643847. The reversal of 643802 is 208346.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 208346 = 2 ⋅104173.

It can be written as a sum of positive squares in only one way, i.e., 591361 + 52441 = 769^2 + 229^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160949 + ... + 160952.

2⁶⁴³⁸⁰² is an apocalyptic number.

643802 is a deficient number, since it is larger than the sum of its proper divisors (321904).

643802 is a wasteful number, since it uses less digits than its factorization.

643802 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321903.

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 643802 is about 802.3727313412. The cubic root of 643802 is about 86.3476999723.

The spelling of 643802 in words is "six hundred forty-three thousand, eight hundred two".