643545101 has 2 divisors, whose sum is σ = 643545102. Its totient is φ = 643545100.

The previous prime is 643545011. The next prime is 643545121. The reversal of 643545101 is 101545346.

It is a happy number.

643545101 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

Together with previous prime (643545011) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 561642601 + 81902500 = 23699^2 + 9050^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643545101 is a prime.

It is a super-2 number, since 2×643545101² = 828300594042200402, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643545121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321772550 + 321772551.

It is an arithmetic number, because the mean of its divisors is an integer number (321772551).

Almost surely, 2^643545101 is an apocalyptic number.

It is an amenable number.

643545101 is a deficient number, since it is larger than the sum of its proper divisors (1).

643545101 is an equidigital number, since it uses as much as digits as its factorization.

643545101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 643545101 is about 25368.1907317018. The cubic root of 643545101 is about 863.3621321653.

The spelling of 643545101 in words is "six hundred forty-three million, five hundred forty-five thousand, one hundred one".