16643939399 has 2 divisors, whose sum is σ = 16643939400. Its totient is φ = 16643939398.

The previous prime is 16643939357. The next prime is 16643939503. The reversal of 16643939399 is 99393934661.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16643939399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16643939329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8321969699 + 8321969700.

It is an arithmetic number, because the mean of its divisors is an integer number (8321969700).

Almost surely, 2^16643939399 is an apocalyptic number.

16643939399 is a deficient number, since it is larger than the sum of its proper divisors (1).

16643939399 is an equidigital number, since it uses as much as digits as its factorization.

16643939399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25509168, while the sum is 62.

The spelling of 16643939399 in words is "sixteen billion, six hundred forty-three million, nine hundred thirty-nine thousand, three hundred ninety-nine".