1155581 has 4 divisors (see below), whose sum is σ = 1320672. Its totient is φ = 990492.

The previous prime is 1155577. The next prime is 1155601. The reversal of 1155581 is 1855511.

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.

It is a cyclic number.

It is not a de Polignac number, because 1155581 - 2² = 1155577 is a prime.

It is a super-2 number, since 2×1155581² = 2670734895122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1155581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1151581) 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, 82535 + ... + 82548.

It is an arithmetic number, because the mean of its divisors is an integer number (330168).

2^1155581 is an apocalyptic number.

It is an amenable number.

1155581 is a deficient number, since it is larger than the sum of its proper divisors (165091).

1155581 is an equidigital number, since it uses as much as digits as its factorization.

1155581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165090.

The product of its digits is 1000, while the sum is 26.

The square root of 1155581 is about 1074.9795346889. The cubic root of 1155581 is about 104.9381646500.

The spelling of 1155581 in words is "one million, one hundred fifty-five thousand, five hundred eighty-one".