1921109549 has 4 divisors (see below), whose sum is σ = 1923160764. Its totient is φ = 1919058336.

The previous prime is 1921109527. The next prime is 1921109563. The reversal of 1921109549 is 9459011291.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 817674025 + 1103435524 = 28595^2 + 33218^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1921109549 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921109249) 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, 1024202 + ... + 1026075.

It is an arithmetic number, because the mean of its divisors is an integer number (480790191).

Almost surely, 2^1921109549 is an apocalyptic number.

It is an amenable number.

1921109549 is a deficient number, since it is larger than the sum of its proper divisors (2051215).

1921109549 is an equidigital number, since it uses as much as digits as its factorization.

1921109549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2051214.

The product of its (nonzero) digits is 29160, while the sum is 41.

The square root of 1921109549 is about 43830.4637096164. The cubic root of 1921109549 is about 1243.1323747994.

The spelling of 1921109549 in words is "one billion, nine hundred twenty-one million, one hundred nine thousand, five hundred forty-nine".