643236 has 36 divisors (see below), whose sum is σ = 1653456. Its totient is φ = 194480.

The previous prime is 643231. The next prime is 643243. The reversal of 643236 is 632346.

643236 = 4² + 5² + ... + 124².

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

It is not an unprimeable number, because it can be changed into a prime (643231) by changing a digit.

643236 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, 1231 + ... + 1673.

2⁶⁴³²³⁶ is an apocalyptic number.

643236 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643236, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (826728).

643236 is an abundant number, since it is smaller than the sum of its proper divisors (1010220).

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

643236 is a wasteful number, since it uses less digits than its factorization.

643236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 472 (or 459 counting only the distinct ones).

The product of its digits is 2592, while the sum is 24.

The square root of 643236 is about 802.0199498766. The cubic root of 643236 is about 86.3223882939.

The spelling of 643236 in words is "six hundred forty-three thousand, two hundred thirty-six".