1011561161 has 12 divisors (see below), whose sum is σ = 1098191052. Its totient is φ = 931334976.

The previous prime is 1011561107. The next prime is 1011561163. The reversal of 1011561161 is 1611651101.

It is a happy number.

1011561161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 6 ways, for example, as 331968400 + 679592761 = 18220^2 + 26069^2 .

It is not a de Polignac number, because 1011561161 - 2⁶ = 1011561097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1011561163) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59555 + ... + 74631.

It is an arithmetic number, because the mean of its divisors is an integer number (91515921).

Almost surely, 2^1011561161 is an apocalyptic number.

It is an amenable number.

1011561161 is a deficient number, since it is larger than the sum of its proper divisors (86629891).

1011561161 is a wasteful number, since it uses less digits than its factorization.

1011561161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15500 (or 15487 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 23.

The square root of 1011561161 is about 31805.0493003863. The cubic root of 1011561161 is about 1003.8389638309.

The spelling of 1011561161 in words is "one billion, eleven million, five hundred sixty-one thousand, one hundred sixty-one".