1921789919623 has 18 divisors (see below), whose sum is σ = 2208262325784. Its totient is φ = 1638348399072.

The previous prime is 1921789919573. The next prime is 1921789919681. The reversal of 1921789919623 is 3269199871291.

It is not a de Polignac number, because 1921789919623 - 2¹⁷ = 1921789788551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921789919123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 729884715 + ... + 729887347.

Almost surely, 2^{1921789919623} is an apocalyptic number.

1921789919623 is a deficient number, since it is larger than the sum of its proper divisors (286472406161).

1921789919623 is an frugal number, since it uses more digits than its factorization.

1921789919623 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5671 (or 2839 counting only the distinct ones).

The product of its digits is 26453952, while the sum is 67.

The spelling of 1921789919623 in words is "one trillion, nine hundred twenty-one billion, seven hundred eighty-nine million, nine hundred nineteen thousand, six hundred twenty-three".