643402 has 16 divisors (see below), whose sum is σ = 1026432. Its totient is φ = 301840.

The previous prime is 643373. The next prime is 643403. The reversal of 643402 is 204346.

It is a super-2 number, since 2×643402² = 827932267208, which contains 22 as substring.

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 643402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643403) by changing a digit.

643402 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3168 + ... + 3364.

It is an arithmetic number, because the mean of its divisors is an integer number (64152).

2⁶⁴³⁴⁰² is an apocalyptic number.

643402 is a deficient number, since it is larger than the sum of its proper divisors (383030).

643402 is a wasteful number, since it uses less digits than its factorization.

643402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 643402 is about 802.1234318981. The cubic root of 643402 is about 86.3298133987.

Adding to 643402 its reverse (204346), we get a palindrome (847748).

The spelling of 643402 in words is "six hundred forty-three thousand, four hundred two".