19890346921 has 8 divisors (see below), whose sum is σ = 20224562688. Its totient is φ = 19556394000.

The previous prime is 19890346913. The next prime is 19890346943. The reversal of 19890346921 is 12964309891.

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 19890346921 - 2³ = 19890346913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19890346981) 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 7 ways as a sum of consecutive naturals, for example, 89976 + ... + 218806.

It is an arithmetic number, because the mean of its divisors is an integer number (2528070336).

Almost surely, 2^19890346921 is an apocalyptic number.

It is an amenable number.

19890346921 is a deficient number, since it is larger than the sum of its proper divisors (334215767).

19890346921 is a wasteful number, since it uses less digits than its factorization.

19890346921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131423.

The product of its (nonzero) digits is 839808, while the sum is 52.

The spelling of 19890346921 in words is "nineteen billion, eight hundred ninety million, three hundred forty-six thousand, nine hundred twenty-one".