643556344357 has 2 divisors, whose sum is σ = 643556344358. Its totient is φ = 643556344356.

The previous prime is 643556344351. The next prime is 643556344373. The reversal of 643556344357 is 753443655346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 552106955521 + 91449388836 = 743039^2 + 302406^2 .

It is a cyclic number.

It is not a de Polignac number, because 643556344357 - 2²⁷ = 643422126629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643556344298 and 643556344307.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643556344351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321778172178 + 321778172179.

It is an arithmetic number, because the mean of its divisors is an integer number (321778172179).

Almost surely, 2^643556344357 is an apocalyptic number.

It is an amenable number.

643556344357 is a deficient number, since it is larger than the sum of its proper divisors (1).

643556344357 is an equidigital number, since it uses as much as digits as its factorization.

643556344357 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432000, while the sum is 55.

The spelling of 643556344357 in words is "six hundred forty-three billion, five hundred fifty-six million, three hundred forty-four thousand, three hundred fifty-seven".