643523172 has 24 divisors (see below), whose sum is σ = 1549992192. Its totient is φ = 207588000.

The previous prime is 643523171. The next prime is 643523189. The reversal of 643523172 is 271325346.

It is not an unprimeable number, because it can be changed into a prime (643523171) 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, 864579 + ... + 865322.

It is an arithmetic number, because the mean of its divisors is an integer number (64583008).

Almost surely, 2^643523172 is an apocalyptic number.

643523172 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

It is an amenable number.

643523172 is an abundant number, since it is smaller than the sum of its proper divisors (906469020).

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

643523172 is a wasteful number, since it uses less digits than its factorization.

643523172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1729939 (or 1729937 counting only the distinct ones).

The product of its digits is 30240, while the sum is 33.

The square root of 643523172 is about 25367.7585135147. The cubic root of 643523172 is about 863.3523256093.

The spelling of 643523172 in words is "six hundred forty-three million, five hundred twenty-three thousand, one hundred seventy-two".