1921966919 has 4 divisors (see below), whose sum is σ = 1940626896. Its totient is φ = 1903306944.

The previous prime is 1921966913. The next prime is 1921966927. The reversal of 1921966919 is 9196691291.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1921966919 - 2²⁰ = 1920918343 is a prime.

It is a super-2 number, since 2×1921966919² = 7387913675460705122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921966913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9329834 + ... + 9330039.

It is an arithmetic number, because the mean of its divisors is an integer number (485156724).

Almost surely, 2^1921966919 is an apocalyptic number.

1921966919 is a deficient number, since it is larger than the sum of its proper divisors (18659977).

1921966919 is a wasteful number, since it uses less digits than its factorization.

1921966919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18659976.

The product of its digits is 472392, while the sum is 53.

The square root of 1921966919 is about 43840.2431448549. The cubic root of 1921966919 is about 1243.3172793838.

The spelling of 1921966919 in words is "one billion, nine hundred twenty-one million, nine hundred sixty-six thousand, nine hundred nineteen".