643051517 has 2 divisors, whose sum is σ = 643051518. Its totient is φ = 643051516.

The previous prime is 643051459. The next prime is 643051529. The reversal of 643051517 is 715150346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 571496836 + 71554681 = 23906^2 + 8459^2 .

It is a cyclic number.

It is not a de Polignac number, because 643051517 - 2²⁰ = 642002941 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643051567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321525758 + 321525759.

It is an arithmetic number, because the mean of its divisors is an integer number (321525759).

Almost surely, 2^643051517 is an apocalyptic number.

It is an amenable number.

643051517 is a deficient number, since it is larger than the sum of its proper divisors (1).

643051517 is an equidigital number, since it uses as much as digits as its factorization.

643051517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12600, while the sum is 32.

The square root of 643051517 is about 25358.4604619445. The cubic root of 643051517 is about 863.1413495414.

The spelling of 643051517 in words is "six hundred forty-three million, fifty-one thousand, five hundred seventeen".