643308420 has 24 divisors (see below), whose sum is σ = 1801263744. Its totient is φ = 171548896.

The previous prime is 643308371. The next prime is 643308427. The reversal of 643308420 is 24803346.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (643308427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5360844 + ... + 5360963.

It is an arithmetic number, because the mean of its divisors is an integer number (75052656).

Almost surely, 2^643308420 is an apocalyptic number.

643308420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643308420 is an abundant number, since it is smaller than the sum of its proper divisors (1157955324).

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

643308420 is a wasteful number, since it uses less digits than its factorization.

643308420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10721819 (or 10721817 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 643308420 is about 25363.5253858765. The cubic root of 643308420 is about 863.2562776477.

The spelling of 643308420 in words is "six hundred forty-three million, three hundred eight thousand, four hundred twenty".