643632 has 80 divisors (see below), whose sum is σ = 1928448. Its totient is φ = 183040.

The previous prime is 643619. The next prime is 643633. The reversal of 643632 is 236346.

It is a Harshad number since it is a multiple of its sum of digits (24).

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

It is a d-powerful number, because it can be written as 6 + 4⁵ + 6³ + 3¹⁰ + 3¹⁰ + 2¹⁹ .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643632.

It is not an unprimeable number, because it can be changed into a prime (643633) by changing a digit.

643632 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 15 ways as a sum of consecutive naturals, for example, 12118 + ... + 12170.

2⁶⁴³⁶³² 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 643632, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (964224).

643632 is an abundant number, since it is smaller than the sum of its proper divisors (1284816).

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

643632 is a wasteful number, since it uses less digits than its factorization.

643632 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98 (or 92 counting only the distinct ones).

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

The square root of 643632 is about 802.2667885436. The cubic root of 643632 is about 86.3400990840.

Adding to 643632 its reverse (236346), we get a palindrome (879978).

It can be divided in two parts, 643 and 632, that added together give a triangular number (1275 = T₅₀).

The spelling of 643632 in words is "six hundred forty-three thousand, six hundred thirty-two".