643212 has 36 divisors (see below), whose sum is σ = 1723176. Its totient is φ = 201600.

The previous prime is 643199. The next prime is 643213. The reversal of 643212 is 212346.

It is a happy number.

643212 is a `hidden beast` number, since 643 + 21 + 2 = 666.

643212 is nontrivially palindromic in base 15.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643212.

It is not an unprimeable number, because it can be changed into a prime (643213) by changing a digit.

643212 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 11 ways as a sum of consecutive naturals, for example, 87 + ... + 1137.

It is an arithmetic number, because the mean of its divisors is an integer number (47866).

2⁶⁴³²¹² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (861588).

643212 is an abundant number, since it is smaller than the sum of its proper divisors (1079964).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

643212 is a wasteful number, since it uses less digits than its factorization.

643212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1078 (or 1073 counting only the distinct ones).

The product of its digits is 288, while the sum is 18.

The square root of 643212 is about 802.0049875157. The cubic root of 643212 is about 86.3213146791.

Adding to 643212 its reverse (212346), we get a palindrome (855558).

The spelling of 643212 in words is "six hundred forty-three thousand, two hundred twelve".