643740 has 24 divisors (see below), whose sum is σ = 1802640. Its totient is φ = 171648.

The previous prime is 643729. The next prime is 643751. The reversal of 643740 is 47346.

643740 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (643729) and next prime (643751).

It is a self number, because there is not a number n which added to its sum of digits gives 643740.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 643740.

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, 5305 + ... + 5424.

It is an arithmetic number, because the mean of its divisors is an integer number (75110).

2⁶⁴³⁷⁴⁰ is an apocalyptic number.

643740 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643740 is an abundant number, since it is smaller than the sum of its proper divisors (1158900).

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

643740 is a wasteful number, since it uses less digits than its factorization.

643740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10741 (or 10739 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 24.

The square root of 643740 is about 802.3340950003. The cubic root of 643740 is about 86.3449280386.

The spelling of 643740 in words is "six hundred forty-three thousand, seven hundred forty".