1011125561 has 2 divisors, whose sum is σ = 1011125562. Its totient is φ = 1011125560.

The previous prime is 1011125537. The next prime is 1011125581. The reversal of 1011125561 is 1655211101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 996349225 + 14776336 = 31565^2 + 3844^2 .

It is a cyclic number.

It is not a de Polignac number, because 1011125561 - 2¹⁸ = 1010863417 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1011125581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 505562780 + 505562781.

It is an arithmetic number, because the mean of its divisors is an integer number (505562781).

Almost surely, 2^1011125561 is an apocalyptic number.

It is an amenable number.

1011125561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1011125561 is an equidigital number, since it uses as much as digits as its factorization.

1011125561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 300, while the sum is 23.

The square root of 1011125561 is about 31798.2005937443. The cubic root of 1011125561 is about 1003.6948515911.

Adding to 1011125561 its reverse (1655211101), we get a palindrome (2666336662).

The spelling of 1011125561 in words is "one billion, eleven million, one hundred twenty-five thousand, five hundred sixty-one".