11561550009 has 16 divisors (see below), whose sum is σ = 16630157952. Its totient is φ = 7117430528.

The previous prime is 11561549999. The next prime is 11561550023. The reversal of 11561550009 is 90005516511.

It is not a de Polignac number, because 11561550009 - 2⁹ = 11561549497 is a prime.

It is a super-2 number, since 2×11561550009² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (11561550079) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2135949 + ... + 2141354.

It is an arithmetic number, because the mean of its divisors is an integer number (1039384872).

Almost surely, 2^11561550009 is an apocalyptic number.

It is an amenable number.

11561550009 is a deficient number, since it is larger than the sum of its proper divisors (5068607943).

11561550009 is a wasteful number, since it uses less digits than its factorization.

11561550009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4277376.

The product of its (nonzero) digits is 6750, while the sum is 33.

The spelling of 11561550009 in words is "eleven billion, five hundred sixty-one million, five hundred fifty thousand, nine".