1011255561 has 6 divisors (see below), whose sum is σ = 1460702490. Its totient is φ = 674170368.

The previous prime is 1011255517. The next prime is 1011255571. The reversal of 1011255561 is 1655521101.

1011255561 is a `hidden beast` number, since 101 + 1 + 2 + 5 + 556 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 999824400 + 11431161 = 31620^2 + 3381^2 .

It is not a de Polignac number, because 1011255561 - 2¹¹ = 1011253513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1011255571) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 56180856 + ... + 56180873.

It is an arithmetic number, because the mean of its divisors is an integer number (243450415).

Almost surely, 2^1011255561 is an apocalyptic number.

It is an amenable number.

1011255561 is a deficient number, since it is larger than the sum of its proper divisors (449446929).

1011255561 is a wasteful number, since it uses less digits than its factorization.

1011255561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112361735 (or 112361732 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 27.

The square root of 1011255561 is about 31800.2446688701. The cubic root of 1011255561 is about 1003.7378646267.

Adding to 1011255561 its reverse (1655521101), we get a palindrome (2666776662).

The spelling of 1011255561 in words is "one billion, eleven million, two hundred fifty-five thousand, five hundred sixty-one".