1109890121 has 4 divisors (see below), whose sum is σ = 1112686212. Its totient is φ = 1107094032.

The previous prime is 1109890097. The next prime is 1109890163. The reversal of 1109890121 is 1210989011.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1210989011 = 1439 ⋅841549.

It can be written as a sum of positive squares in 2 ways, for example, as 420250000 + 689640121 = 20500^2 + 26261^2 .

It is a cyclic number.

It is not a de Polignac number, because 1109890121 - 2¹⁰ = 1109889097 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 (1109890021) 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, 1397450 + ... + 1398243.

It is an arithmetic number, because the mean of its divisors is an integer number (278171553).

Almost surely, 2^1109890121 is an apocalyptic number.

It is an amenable number.

1109890121 is a deficient number, since it is larger than the sum of its proper divisors (2796091).

1109890121 is an equidigital number, since it uses as much as digits as its factorization.

1109890121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2796090.

The product of its (nonzero) digits is 1296, while the sum is 32.

The square root of 1109890121 is about 33315.0134473934. The cubic root of 1109890121 is about 1035.3646395807.

The spelling of 1109890121 in words is "one billion, one hundred nine million, eight hundred ninety thousand, one hundred twenty-one".