643534004473 has 2 divisors, whose sum is σ = 643534004474. Its totient is φ = 643534004472.

The previous prime is 643534004437. The next prime is 643534004479. The reversal of 643534004473 is 374400435346.

Together with previous prime (643534004437) 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., 626018011369 + 17515993104 = 791213^2 + 132348^2 .

It is a cyclic number.

It is not a de Polignac number, because 643534004473 - 2⁹ = 643534003961 is a prime.

It is not a weakly prime, because it can be changed into another prime (643534004479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321767002236 + 321767002237.

It is an arithmetic number, because the mean of its divisors is an integer number (321767002237).

Almost surely, 2^643534004473 is an apocalyptic number.

It is an amenable number.

643534004473 is a deficient number, since it is larger than the sum of its proper divisors (1).

643534004473 is an equidigital number, since it uses as much as digits as its factorization.

643534004473 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1451520, while the sum is 43.

The spelling of 643534004473 in words is "six hundred forty-three billion, five hundred thirty-four million, four thousand, four hundred seventy-three".