19663939 has 4 divisors (see below), whose sum is σ = 19688656. Its totient is φ = 19639224.

The previous prime is 19663877. The next prime is 19663961. The reversal of 19663939 is 93936691.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19663939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19663979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11124 + ... + 12769.

It is an arithmetic number, because the mean of its divisors is an integer number (4922164).

Almost surely, 2^19663939 is an apocalyptic number.

19663939 is a deficient number, since it is larger than the sum of its proper divisors (24717).

19663939 is an equidigital number, since it uses as much as digits as its factorization.

19663939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24716.

The product of its digits is 236196, while the sum is 46.

The square root of 19663939 is about 4434.4040185802. The cubic root of 19663939 is about 269.9128159296.

It can be divided in two parts, 19663 and 939, that added together give a palindrome (20602).

The spelling of 19663939 in words is "nineteen million, six hundred sixty-three thousand, nine hundred thirty-nine".