643572 has 48 divisors (see below), whose sum is σ = 1713600. Its totient is φ = 208800.

The previous prime is 643567. The next prime is 643583. The reversal of 643572 is 275346.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

643572 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6322 + ... + 6422.

It is an arithmetic number, because the mean of its divisors is an integer number (35700).

2⁶⁴³⁵⁷² 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 643572, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (856800).

643572 is an abundant number, since it is smaller than the sum of its proper divisors (1070028).

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

643572 is a wasteful number, since it uses less digits than its factorization.

643572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173 (or 165 counting only the distinct ones).

The product of its digits is 5040, while the sum is 27.

The square root of 643572 is about 802.2293936275. The cubic root of 643572 is about 86.3374160980.

Subtracting from 643572 its sum of digits (27), we obtain a triangular number (643545 = T₁₁₃₄).

The spelling of 643572 in words is "six hundred forty-three thousand, five hundred seventy-two".