643922 has 4 divisors (see below), whose sum is σ = 965886. Its totient is φ = 321960.

The previous prime is 643919. The next prime is 643927. The reversal of 643922 is 229346.

643922 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 534361 + 109561 = 731^2 + 331^2 .

It is a junction number, because it is equal to n+sod(n) for n = 643891 and 643900.

It is not an unprimeable number, because it can be changed into a prime (643927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160979 + ... + 160982.

2⁶⁴³⁹²² is an apocalyptic number.

643922 is a deficient number, since it is larger than the sum of its proper divisors (321964).

643922 is a wasteful number, since it uses less digits than its factorization.

643922 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321963.

The product of its digits is 2592, while the sum is 26.

The square root of 643922 is about 802.4475060713. The cubic root of 643922 is about 86.3530644996.

The spelling of 643922 in words is "six hundred forty-three thousand, nine hundred twenty-two".