19890921107 has 4 divisors (see below), whose sum is σ = 19891212960. Its totient is φ = 19890629256.

The previous prime is 19890921067. The next prime is 19890921109. The reversal of 19890921107 is 70112909891.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 19890921107 - 2¹⁰ = 19890920083 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19890921109) 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, 16769 + ... + 200157.

It is an arithmetic number, because the mean of its divisors is an integer number (4972803240).

Almost surely, 2^19890921107 is an apocalyptic number.

19890921107 is a deficient number, since it is larger than the sum of its proper divisors (291853).

19890921107 is a wasteful number, since it uses less digits than its factorization.

19890921107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291852.

The product of its (nonzero) digits is 81648, while the sum is 47.

The spelling of 19890921107 in words is "nineteen billion, eight hundred ninety million, nine hundred twenty-one thousand, one hundred seven".