1111555521 has 8 divisors (see below), whose sum is σ = 1646748960. Its totient is φ = 741036996.

The previous prime is 1111555439. The next prime is 1111555541. The reversal of 1111555521 is 1255551111.

It is a happy number.

It is not a de Polignac number, because 1111555521 - 2¹⁴ = 1111539137 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 41168723 = 1111555521 / (1 + 1 + 1 + 1 + 5 + 5 + 5 + 5 + 2 + 1).

It is not an unprimeable number, because it can be changed into a prime (1111555541) 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 7 ways as a sum of consecutive naturals, for example, 20584335 + ... + 20584388.

It is an arithmetic number, because the mean of its divisors is an integer number (205843620).

Almost surely, 2^1111555521 is an apocalyptic number.

It is an amenable number.

1111555521 is a deficient number, since it is larger than the sum of its proper divisors (535193439).

1111555521 is an equidigital number, since it uses as much as digits as its factorization.

1111555521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41168732 (or 41168726 counting only the distinct ones).

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

The square root of 1111555521 is about 33339.9988152369. The cubic root of 1111555521 is about 1035.8822387303.

The spelling of 1111555521 in words is "one billion, one hundred eleven million, five hundred fifty-five thousand, five hundred twenty-one".