643522253 has 4 divisors (see below), whose sum is σ = 702024288. Its totient is φ = 585020220.

The previous prime is 643522249. The next prime is 643522279. The reversal of 643522253 is 352225346.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 643522253 - 2² = 643522249 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643522213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29251001 + ... + 29251022.

It is an arithmetic number, because the mean of its divisors is an integer number (175506072).

Almost surely, 2^643522253 is an apocalyptic number.

It is an amenable number.

643522253 is a deficient number, since it is larger than the sum of its proper divisors (58502035).

643522253 is a wasteful number, since it uses less digits than its factorization.

643522253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58502034.

The product of its digits is 43200, while the sum is 32.

The square root of 643522253 is about 25367.7403999647. The cubic root of 643522253 is about 863.3519146315.

Adding to 643522253 its reverse (352225346), we get a palindrome (995747599).

The spelling of 643522253 in words is "six hundred forty-three million, five hundred twenty-two thousand, two hundred fifty-three".