643522741 has 4 divisors (see below), whose sum is σ = 643591872. Its totient is φ = 643453612.

The previous prime is 643522729. The next prime is 643522751. The reversal of 643522741 is 147225346.

643522741 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 643522741 - 2¹⁹ = 642998453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 643522697 and 643522706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643522751) 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, 17935 + ... + 40108.

It is an arithmetic number, because the mean of its divisors is an integer number (160897968).

Almost surely, 2^643522741 is an apocalyptic number.

It is an amenable number.

643522741 is a deficient number, since it is larger than the sum of its proper divisors (69131).

643522741 is a wasteful number, since it uses less digits than its factorization.

643522741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69130.

The product of its digits is 40320, while the sum is 34.

The square root of 643522741 is about 25367.7500184782. The cubic root of 643522741 is about 863.3521328657.

The spelling of 643522741 in words is "six hundred forty-three million, five hundred twenty-two thousand, seven hundred forty-one".