643629617677 has 2 divisors, whose sum is σ = 643629617678. Its totient is φ = 643629617676.

The previous prime is 643629617647. The next prime is 643629617747. The reversal of 643629617677 is 776716926346.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 600789311236 + 42840306441 = 775106^2 + 206979^2 .

It is a cyclic number.

It is not a de Polignac number, because 643629617677 - 2⁷ = 643629617549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643629617647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321814808838 + 321814808839.

It is an arithmetic number, because the mean of its divisors is an integer number (321814808839).

Almost surely, 2^643629617677 is an apocalyptic number.

It is an amenable number.

643629617677 is a deficient number, since it is larger than the sum of its proper divisors (1).

643629617677 is an equidigital number, since it uses as much as digits as its factorization.

643629617677 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96018048, while the sum is 64.

The spelling of 643629617677 in words is "six hundred forty-three billion, six hundred twenty-nine million, six hundred seventeen thousand, six hundred seventy-seven".