1115555121 has 12 divisors (see below), whose sum is σ = 1633431748. Its totient is φ = 733515264.

The previous prime is 1115555099. The next prime is 1115555141. The reversal of 1115555121 is 1215555111.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 971194896 + 144360225 = 31164^2 + 12015^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1115555121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1115555141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 848320 + ... + 849633.

Almost surely, 2^1115555121 is an apocalyptic number.

It is an amenable number.

1115555121 is a deficient number, since it is larger than the sum of its proper divisors (517876627).

1115555121 is a wasteful number, since it uses less digits than its factorization.

1115555121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1698032 (or 1698029 counting only the distinct ones).

The product of its digits is 1250, while the sum is 27.

The square root of 1115555121 is about 33399.9269609980. The cubic root of 1115555121 is about 1037.1231889665.

The spelling of 1115555121 in words is "one billion, one hundred fifteen million, five hundred fifty-five thousand, one hundred twenty-one".