19844396989 has 4 divisors (see below), whose sum is σ = 19844858880. Its totient is φ = 19843935100.

The previous prime is 19844396953. The next prime is 19844397049. The reversal of 19844396989 is 98969344891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19844396989 - 2¹⁹ = 19843872701 is a prime.

It is a super-2 number, since 2×19844396989² (a number of 21 digits) contains 22 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 (19844396489) 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, 159037 + ... + 254914.

It is an arithmetic number, because the mean of its divisors is an integer number (4961214720).

Almost surely, 2^19844396989 is an apocalyptic number.

It is an amenable number.

19844396989 is a deficient number, since it is larger than the sum of its proper divisors (461891).

19844396989 is an equidigital number, since it uses as much as digits as its factorization.

19844396989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461890.

The product of its digits is 120932352, while the sum is 70.

The spelling of 19844396989 in words is "nineteen billion, eight hundred forty-four million, three hundred ninety-six thousand, nine hundred eighty-nine".