643571257 has 16 divisors (see below), whose sum is σ = 770457600. Its totient is φ = 525607632.

The previous prime is 643571231. The next prime is 643571263. The reversal of 643571257 is 752175346.

643571257 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 643571257 - 2¹¹ = 643569209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643571267) 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, 34744 + ... + 49942.

It is an arithmetic number, because the mean of its divisors is an integer number (48153600).

Almost surely, 2^643571257 is an apocalyptic number.

It is an amenable number.

643571257 is a deficient number, since it is larger than the sum of its proper divisors (126886343).

643571257 is a wasteful number, since it uses less digits than its factorization.

643571257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15492.

The product of its digits is 176400, while the sum is 40.

The square root of 643571257 is about 25368.7062539657. The cubic root of 643571257 is about 863.3738287265.

The spelling of 643571257 in words is "six hundred forty-three million, five hundred seventy-one thousand, two hundred fifty-seven".