1115581 has 2 divisors, whose sum is σ = 1115582. Its totient is φ = 1115580.

The previous prime is 1115579. The next prime is 1115599. The reversal of 1115581 is 1855111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1020100 + 95481 = 1010^2 + 309^2 .

It is a cyclic number.

It is not a de Polignac number, because 1115581 - 2¹ = 1115579 is a prime.

It is a super-2 number, since 2×1115581² = 2489041935122, which contains 22 as substring.

Together with 1115579, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1115501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 557790 + 557791.

It is an arithmetic number, because the mean of its divisors is an integer number (557791).

2^1115581 is an apocalyptic number.

It is an amenable number.

1115581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1115581 is an equidigital number, since it uses as much as digits as its factorization.

1115581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 200, while the sum is 22.

The square root of 1115581 is about 1056.2106797415. The cubic root of 1115581 is about 103.7131208742.

It can be divided in two parts, 11155 and 81, that added together give a square (11236 = 106²).

The spelling of 1115581 in words is "one million, one hundred fifteen thousand, five hundred eighty-one".