11121555121 has 4 divisors (see below), whose sum is σ = 11128736500. Its totient is φ = 11114373744.

The previous prime is 11121555113. The next prime is 11121555157. The reversal of 11121555121 is 12155512111.

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 5540718096 + 5580837025 = 74436^2 + 74705^2 .

It is a cyclic number.

It is not a de Polignac number, because 11121555121 - 2³ = 11121555113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11121558121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3588366 + ... + 3591463.

It is an arithmetic number, because the mean of its divisors is an integer number (2782184125).

Almost surely, 2^11121555121 is an apocalyptic number.

It is an amenable number.

11121555121 is a deficient number, since it is larger than the sum of its proper divisors (7181379).

11121555121 is an equidigital number, since it uses as much as digits as its factorization.

11121555121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7181378.

The product of its digits is 500, while the sum is 25.

The spelling of 11121555121 in words is "eleven billion, one hundred twenty-one million, five hundred fifty-five thousand, one hundred twenty-one".