643522057 has 4 divisors (see below), whose sum is σ = 645431956. Its totient is φ = 641612160.

The previous prime is 643522049. The next prime is 643522091. The reversal of 643522057 is 750225346.

643522057 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.

It can be written as a sum of positive squares in 2 ways, for example, as 125686521 + 517835536 = 11211^2 + 22756^2 .

It is a cyclic number.

It is not a de Polignac number, because 643522057 - 2³ = 643522049 is a prime.

It is a super-2 number, since 2×643522057² = 828241275691022498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643523057) 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, 954444 + ... + 955117.

It is an arithmetic number, because the mean of its divisors is an integer number (161357989).

Almost surely, 2^643522057 is an apocalyptic number.

It is an amenable number.

643522057 is a deficient number, since it is larger than the sum of its proper divisors (1909899).

643522057 is a wasteful number, since it uses less digits than its factorization.

643522057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1909898.

The product of its (nonzero) digits is 50400, while the sum is 34.

The square root of 643522057 is about 25367.7365367902. The cubic root of 643522057 is about 863.3518269800.

The spelling of 643522057 in words is "six hundred forty-three million, five hundred twenty-two thousand, fifty-seven".