643521252 has 48 divisors (see below), whose sum is σ = 1694548800. Its totient is φ = 188280960.

The previous prime is 643521233. The next prime is 643521259. The reversal of 643521252 is 252125346.

It is not an unprimeable number, because it can be changed into a prime (643521259) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 80227 + ... + 87882.

It is an arithmetic number, because the mean of its divisors is an integer number (35303100).

Almost surely, 2^643521252 is an apocalyptic number.

It is an amenable number.

643521252 is an abundant number, since it is smaller than the sum of its proper divisors (1051027548).

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

643521252 is a wasteful number, since it uses less digits than its factorization.

643521252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168156 (or 168154 counting only the distinct ones).

The product of its digits is 14400, while the sum is 30.

The square root of 643521252 is about 25367.7206701745. The cubic root of 643521252 is about 863.3514669828.

Adding to 643521252 its reverse (252125346), we get a palindrome (895646598).

The spelling of 643521252 in words is "six hundred forty-three million, five hundred twenty-one thousand, two hundred fifty-two".