643779412847 has 2 divisors, whose sum is σ = 643779412848. Its totient is φ = 643779412846.

The previous prime is 643779412831. The next prime is 643779412877. The reversal of 643779412847 is 748214977346.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 643779412847 - 2⁴ = 643779412831 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643779412847.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643779412877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321889706423 + 321889706424.

It is an arithmetic number, because the mean of its divisors is an integer number (321889706424).

Almost surely, 2^643779412847 is an apocalyptic number.

643779412847 is a deficient number, since it is larger than the sum of its proper divisors (1).

643779412847 is an equidigital number, since it uses as much as digits as its factorization.

643779412847 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56899584, while the sum is 62.

The spelling of 643779412847 in words is "six hundred forty-three billion, seven hundred seventy-nine million, four hundred twelve thousand, eight hundred forty-seven".