19664048639 has 4 divisors (see below), whose sum is σ = 19698129024. Its totient is φ = 19629968256.

The previous prime is 19664048629. The next prime is 19664048653. The reversal of 19664048639 is 93684046691.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 19664048639 - 2⁴ = 19664048623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19664048629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17039327 + ... + 17040480.

It is an arithmetic number, because the mean of its divisors is an integer number (4924532256).

Almost surely, 2^19664048639 is an apocalyptic number.

19664048639 is a deficient number, since it is larger than the sum of its proper divisors (34080385).

19664048639 is an equidigital number, since it uses as much as digits as its factorization.

19664048639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34080384.

The product of its (nonzero) digits is 6718464, while the sum is 56.

The spelling of 19664048639 in words is "nineteen billion, six hundred sixty-four million, forty-eight thousand, six hundred thirty-nine".