643543697 has 2 divisors, whose sum is σ = 643543698. Its totient is φ = 643543696.

The previous prime is 643543673. The next prime is 643543741. The reversal of 643543697 is 796345346.

643543697 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 628805776 + 14737921 = 25076^2 + 3839^2 .

It is a cyclic number.

It is not a de Polignac number, because 643543697 - 2⁸ = 643543441 is a prime.

It is not a weakly prime, because it can be changed into another prime (643543097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321771848 + 321771849.

It is an arithmetic number, because the mean of its divisors is an integer number (321771849).

Almost surely, 2^643543697 is an apocalyptic number.

It is an amenable number.

643543697 is a deficient number, since it is larger than the sum of its proper divisors (1).

643543697 is an equidigital number, since it uses as much as digits as its factorization.

643543697 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1632960, while the sum is 47.

The square root of 643543697 is about 25368.1630592363. The cubic root of 643543697 is about 863.3615043091.

The spelling of 643543697 in words is "six hundred forty-three million, five hundred forty-three thousand, six hundred ninety-seven".