643058681 has 2 divisors, whose sum is σ = 643058682. Its totient is φ = 643058680.

The previous prime is 643058671. The next prime is 643058707. The reversal of 643058681 is 186850346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 343768681 + 299290000 = 18541^2 + 17300^2 .

It is a cyclic number.

It is not a de Polignac number, because 643058681 - 2²² = 638864377 is a prime.

It is a super-2 number, since 2×643058681² = 827048934418919522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (643058621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321529340 + 321529341.

It is an arithmetic number, because the mean of its divisors is an integer number (321529341).

Almost surely, 2^643058681 is an apocalyptic number.

It is an amenable number.

643058681 is a deficient number, since it is larger than the sum of its proper divisors (1).

643058681 is an equidigital number, since it uses as much as digits as its factorization.

643058681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 138240, while the sum is 41.

The square root of 643058681 is about 25358.6017161830. The cubic root of 643058681 is about 863.1445548427.

The spelling of 643058681 in words is "six hundred forty-three million, fifty-eight thousand, six hundred eighty-one".