19878968653 has 4 divisors (see below), whose sum is σ = 20012384700. Its totient is φ = 19745552608.

The previous prime is 19878968597. The next prime is 19878968663. The reversal of 19878968653 is 35686987891.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6809220324 + 13069748329 = 82518^2 + 114323^2 .

It is a cyclic number.

It is not a de Polignac number, because 19878968653 - 2²⁹ = 19342097741 is a prime.

It is a super-4 number, since 4×19878968653⁴ (a number of 42 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19878968663) 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, 66707800 + ... + 66708097.

It is an arithmetic number, because the mean of its divisors is an integer number (5003096175).

Almost surely, 2^19878968653 is an apocalyptic number.

It is an amenable number.

19878968653 is a deficient number, since it is larger than the sum of its proper divisors (133416047).

19878968653 is a wasteful number, since it uses less digits than its factorization.

19878968653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133416046.

The product of its digits is 156764160, while the sum is 70.

The spelling of 19878968653 in words is "nineteen billion, eight hundred seventy-eight million, nine hundred sixty-eight thousand, six hundred fifty-three".