63999643 has 2 divisors, whose sum is σ = 63999644. Its totient is φ = 63999642.

The previous prime is 63999641. The next prime is 63999653. The reversal of 63999643 is 34699936.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 63999643 - 2¹ = 63999641 is a prime.

Together with 63999641, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (63999641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31999821 + 31999822.

It is an arithmetic number, because the mean of its divisors is an integer number (31999822).

Almost surely, 2^63999643 is an apocalyptic number.

63999643 is a deficient number, since it is larger than the sum of its proper divisors (1).

63999643 is an equidigital number, since it uses as much as digits as its factorization.

63999643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 944784, while the sum is 49.

The square root of 63999643 is about 7999.9776874689. The cubic root of 63999643 is about 399.9992562486. Note that the first 3 decimals are identical.

The spelling of 63999643 in words is "sixty-three million, nine hundred ninety-nine thousand, six hundred forty-three".