1181890121 has 4 divisors (see below), whose sum is σ = 1233276672. Its totient is φ = 1130503572.

The previous prime is 1181890109. The next prime is 1181890123. The reversal of 1181890121 is 1210981811.

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: 1210981811 = 13 ⋅93152447.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1181890121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1181890123) 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, 25693241 + ... + 25693286.

It is an arithmetic number, because the mean of its divisors is an integer number (308319168).

Almost surely, 2^1181890121 is an apocalyptic number.

It is an amenable number.

1181890121 is a deficient number, since it is larger than the sum of its proper divisors (51386551).

1181890121 is an equidigital number, since it uses as much as digits as its factorization.

1181890121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51386550.

The product of its (nonzero) digits is 1152, while the sum is 32.

The square root of 1181890121 is about 34378.6288411856. The cubic root of 1181890121 is about 1057.2857223725.

The spelling of 1181890121 in words is "one billion, one hundred eighty-one million, eight hundred ninety thousand, one hundred twenty-one".