643373663 has 2 divisors, whose sum is σ = 643373664. Its totient is φ = 643373662.

The previous prime is 643373651. The next prime is 643373677. The reversal of 643373663 is 366373346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643373663 - 2⁸ = 643373407 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643373663.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643373693) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321686831 + 321686832.

It is an arithmetic number, because the mean of its divisors is an integer number (321686832).

Almost surely, 2^643373663 is an apocalyptic number.

643373663 is a deficient number, since it is larger than the sum of its proper divisors (1).

643373663 is an equidigital number, since it uses as much as digits as its factorization.

643373663 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 41.

The square root of 643373663 is about 25364.8115112255. The cubic root of 643373663 is about 863.2854598791.

The spelling of 643373663 in words is "six hundred forty-three million, three hundred seventy-three thousand, six hundred sixty-three".