643952 has 20 divisors (see below), whose sum is σ = 1260336. Its totient is φ = 318720.

The previous prime is 643949. The next prime is 643957. The reversal of 643952 is 259346.

643952 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2552 + ... + 2792.

643952 is a Friedman number, since it can be written as ((9+2)^5-63)*4, using all its digits and the basic arithmetic operations.

2⁶⁴³⁹⁵² is an apocalyptic number.

It is an amenable number.

643952 is a deficient number, since it is larger than the sum of its proper divisors (616384).

643952 is a wasteful number, since it uses less digits than its factorization.

643952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416 (or 410 counting only the distinct ones).

The product of its digits is 6480, while the sum is 29.

The square root of 643952 is about 802.4661986651. The cubic root of 643952 is about 86.3544055273.

The spelling of 643952 in words is "six hundred forty-three thousand, nine hundred fifty-two".