1921719689 has 2 divisors, whose sum is σ = 1921719690. Its totient is φ = 1921719688.

The previous prime is 1921719599. The next prime is 1921719731. The reversal of 1921719689 is 9869171291.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1499006089 + 422713600 = 38717^2 + 20560^2 .

It is a cyclic number.

It is not a de Polignac number, because 1921719689 - 2⁸ = 1921719433 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1921719689.

It is not a weakly prime, because it can be changed into another prime (1921719589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960859844 + 960859845.

It is an arithmetic number, because the mean of its divisors is an integer number (960859845).

Almost surely, 2^1921719689 is an apocalyptic number.

It is an amenable number.

1921719689 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921719689 is an equidigital number, since it uses as much as digits as its factorization.

1921719689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 53.

The square root of 1921719689 is about 43837.4233845923. The cubic root of 1921719689 is about 1243.2639662025.

The spelling of 1921719689 in words is "one billion, nine hundred twenty-one million, seven hundred nineteen thousand, six hundred eighty-nine".