643465320 has 128 divisors (see below), whose sum is σ = 1975242240. Its totient is φ = 167650560.

The previous prime is 643465313. The next prime is 643465321. The reversal of 643465320 is 23564346.

It is not an unprimeable number, because it can be changed into a prime (643465321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1310275 + ... + 1310765.

It is an arithmetic number, because the mean of its divisors is an integer number (15431580).

Almost surely, 2^643465320 is an apocalyptic number.

643465320 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643465320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (987621120).

643465320 is an abundant number, since it is smaller than the sum of its proper divisors (1331776920).

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

643465320 is a wasteful number, since it uses less digits than its factorization.

643465320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 735 (or 731 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 33.

The square root of 643465320 is about 25366.6182215919. The cubic root of 643465320 is about 863.3264533705.

The spelling of 643465320 in words is "six hundred forty-three million, four hundred sixty-five thousand, three hundred twenty".