643396340 has 12 divisors (see below), whose sum is σ = 1351132356. Its totient is φ = 257358528.

The previous prime is 643396337. The next prime is 643396381. The reversal of 643396340 is 43693346.

It can be written as a sum of positive squares in 2 ways, for example, as 126652516 + 516743824 = 11254^2 + 22732^2 .

It is a junction number, because it is equal to n+sod(n) for n = 643396294 and 643396303.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16084889 + ... + 16084928.

It is an arithmetic number, because the mean of its divisors is an integer number (112594363).

Almost surely, 2^643396340 is an apocalyptic number.

It is an amenable number.

643396340 is an abundant number, since it is smaller than the sum of its proper divisors (707736016).

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

643396340 is a wasteful number, since it uses less digits than its factorization.

643396340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32169826 (or 32169824 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 38.

The square root of 643396340 is about 25365.2585242098. The cubic root of 643396340 is about 863.2956025046.

The spelling of 643396340 in words is "six hundred forty-three million, three hundred ninety-six thousand, three hundred forty".