19721246689 has 8 divisors (see below), whose sum is σ = 19930738688. Its totient is φ = 19512601920.

The previous prime is 19721246687. The next prime is 19721246711. The reversal of 19721246689 is 98664212791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19721246689 - 2¹ = 19721246687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19721246683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164952 + ... + 258169.

It is an arithmetic number, because the mean of its divisors is an integer number (2491342336).

Almost surely, 2^19721246689 is an apocalyptic number.

It is an amenable number.

19721246689 is a deficient number, since it is larger than the sum of its proper divisors (209491999).

19721246689 is a wasteful number, since it uses less digits than its factorization.

19721246689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423615.

The product of its digits is 2612736, while the sum is 55.

The spelling of 19721246689 in words is "nineteen billion, seven hundred twenty-one million, two hundred forty-six thousand, six hundred eighty-nine".