643251242571 has 24 divisors (see below), whose sum is σ = 997726764240. Its totient is φ = 367560732672.

The previous prime is 643251242551. The next prime is 643251242609. The reversal of 643251242571 is 175242152346.

It is a happy number.

It is not a de Polignac number, because 643251242571 - 2⁹ = 643251242059 is a prime.

It is a super-2 number, since 2×643251242571² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (643251242551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7691935 + ... + 7775111.

It is an arithmetic number, because the mean of its divisors is an integer number (41571948510).

Almost surely, 2^643251242571 is an apocalyptic number.

643251242571 is a deficient number, since it is larger than the sum of its proper divisors (354475521669).

643251242571 is a wasteful number, since it uses less digits than its factorization.

643251242571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135803 (or 135796 counting only the distinct ones).

The product of its digits is 403200, while the sum is 42.

The spelling of 643251242571 in words is "six hundred forty-three billion, two hundred fifty-one million, two hundred forty-two thousand, five hundred seventy-one".