6399945529 has 2 divisors, whose sum is σ = 6399945530. Its totient is φ = 6399945528.

The previous prime is 6399945521. The next prime is 6399945557. The reversal of 6399945529 is 9255499936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5528219904 + 871725625 = 74352^2 + 29525^2 .

It is a cyclic number.

It is not a de Polignac number, because 6399945529 - 2³ = 6399945521 is a prime.

It is not a weakly prime, because it can be changed into another prime (6399945521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3199972764 + 3199972765.

It is an arithmetic number, because the mean of its divisors is an integer number (3199972765).

Almost surely, 2^6399945529 is an apocalyptic number.

It is an amenable number.

6399945529 is a deficient number, since it is larger than the sum of its proper divisors (1).

6399945529 is an equidigital number, since it uses as much as digits as its factorization.

6399945529 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23619600, while the sum is 61.

The square root of 6399945529 is about 79999.6595555256. The cubic root of 6399945529 is about 1856.6302660971.

The spelling of 6399945529 in words is "six billion, three hundred ninety-nine million, nine hundred forty-five thousand, five hundred twenty-nine".