18923021909 has 8 divisors (see below), whose sum is σ = 21540831552. Its totient is φ = 16454801440.

The previous prime is 18923021881. The next prime is 18923021951. The reversal of 18923021909 is 90912032981.

It is a happy number.

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

It is not a de Polignac number, because 18923021909 - 2²⁰ = 18921973333 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18923021909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18923021969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37397024 + ... + 37397529.

It is an arithmetic number, because the mean of its divisors is an integer number (2692603944).

Almost surely, 2^18923021909 is an apocalyptic number.

It is an amenable number.

18923021909 is a deficient number, since it is larger than the sum of its proper divisors (2617809643).

18923021909 is a wasteful number, since it uses less digits than its factorization.

18923021909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74794587.

The product of its (nonzero) digits is 69984, while the sum is 44.

The spelling of 18923021909 in words is "eighteen billion, nine hundred twenty-three million, twenty-one thousand, nine hundred nine".