1155457561 has 4 divisors (see below), whose sum is σ = 1155895092. Its totient is φ = 1155020032.

The previous prime is 1155457559. The next prime is 1155457573. The reversal of 1155457561 is 1657545511.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1657545511 = 2753 ⋅602087.

It can be written as a sum of positive squares in 2 ways, for example, as 931775625 + 223681936 = 30525^2 + 14956^2 .

It is a cyclic number.

It is not a de Polignac number, because 1155457561 - 2¹ = 1155457559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1155457591) 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, 214780 + ... + 220093.

It is an arithmetic number, because the mean of its divisors is an integer number (288973773).

Almost surely, 2^1155457561 is an apocalyptic number.

It is an amenable number.

1155457561 is a deficient number, since it is larger than the sum of its proper divisors (437531).

1155457561 is an equidigital number, since it uses as much as digits as its factorization.

1155457561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437530.

The product of its digits is 105000, while the sum is 40.

The square root of 1155457561 is about 33992.0220198799. The cubic root of 1155457561 is about 1049.3442802363.

The spelling of 1155457561 in words is "one billion, one hundred fifty-five million, four hundred fifty-seven thousand, five hundred sixty-one".