19433389921 has 4 divisors (see below), whose sum is σ = 21200061744. Its totient is φ = 17666718100.

The previous prime is 19433389903. The next prime is 19433389939. The reversal of 19433389921 is 12998333491.

It is a happy number.

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 an interprime number because it is at equal distance from previous prime (19433389903) and next prime (19433389939).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19433389921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19433389951) 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, 883335895 + ... + 883335916.

It is an arithmetic number, because the mean of its divisors is an integer number (5300015436).

Almost surely, 2^19433389921 is an apocalyptic number.

19433389921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19433389921 is a deficient number, since it is larger than the sum of its proper divisors (1766671823).

19433389921 is a wasteful number, since it uses less digits than its factorization.

19433389921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1766671822.

The product of its digits is 1259712, while the sum is 52.

The spelling of 19433389921 in words is "nineteen billion, four hundred thirty-three million, three hundred eighty-nine thousand, nine hundred twenty-one".