643505626349 has 2 divisors, whose sum is σ = 643505626350. Its totient is φ = 643505626348.

The previous prime is 643505626333. The next prime is 643505626453. The reversal of 643505626349 is 943626505346.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 489090422500 + 154415203849 = 699350^2 + 392957^2 .

It is a cyclic number.

It is not a de Polignac number, because 643505626349 - 2⁴ = 643505626333 is a prime.

It is a super-2 number, since 2×643505626349² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 643505626349.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643505626849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321752813174 + 321752813175.

It is an arithmetic number, because the mean of its divisors is an integer number (321752813175).

Almost surely, 2^643505626349 is an apocalyptic number.

It is an amenable number.

643505626349 is a deficient number, since it is larger than the sum of its proper divisors (1).

643505626349 is an equidigital number, since it uses as much as digits as its factorization.

643505626349 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13996800, while the sum is 53.

The spelling of 643505626349 in words is "six hundred forty-three billion, five hundred five million, six hundred twenty-six thousand, three hundred forty-nine".