1921219689 has 4 divisors (see below), whose sum is σ = 2561626256. Its totient is φ = 1280813124.

The previous prime is 1921219681. The next prime is 1921219763. The reversal of 1921219689 is 9869121291.

1921219689 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9869121291 = 3 ⋅3289707097.

It is not a de Polignac number, because 1921219689 - 2³ = 1921219681 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1921219681) 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, 320203279 + ... + 320203284.

It is an arithmetic number, because the mean of its divisors is an integer number (640406564).

Almost surely, 2^1921219689 is an apocalyptic number.

It is an amenable number.

1921219689 is a deficient number, since it is larger than the sum of its proper divisors (640406567).

1921219689 is an equidigital number, since it uses as much as digits as its factorization.

1921219689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640406566.

The product of its digits is 139968, while the sum is 48.

The square root of 1921219689 is about 43831.7201236730. The cubic root of 1921219689 is about 1243.1561312067.

The spelling of 1921219689 in words is "one billion, nine hundred twenty-one million, two hundred nineteen thousand, six hundred eighty-nine".