643974 has 16 divisors (see below), whose sum is σ = 1332720. Its totient is φ = 207200.

The previous prime is 643969. The next prime is 643991. The reversal of 643974 is 479346.

643974 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1677 + ... + 2024.

It is an arithmetic number, because the mean of its divisors is an integer number (83295).

2⁶⁴³⁹⁷⁴ is an apocalyptic number.

643974 is an abundant number, since it is smaller than the sum of its proper divisors (688746).

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

643974 is a wasteful number, since it uses less digits than its factorization.

643974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3735.

The product of its digits is 18144, while the sum is 33.

The square root of 643974 is about 802.4799062905. The cubic root of 643974 is about 86.3553889211.

The spelling of 643974 in words is "six hundred forty-three thousand, nine hundred seventy-four".