11515512861 has 6 divisors (see below), whose sum is σ = 16633518590. Its totient is φ = 7677008568.

The previous prime is 11515512857. The next prime is 11515512871. The reversal of 11515512861 is 16821551511.

11515512861 is a `hidden beast` number, since 11 + 51 + 5 + 512 + 86 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 11476836900 + 38675961 = 107130^2 + 6219^2 .

It is not a de Polignac number, because 11515512861 - 2² = 11515512857 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11515512871) 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, 639750706 + ... + 639750723.

Almost surely, 2^11515512861 is an apocalyptic number.

It is an amenable number.

11515512861 is a deficient number, since it is larger than the sum of its proper divisors (5118005729).

11515512861 is a wasteful number, since it uses less digits than its factorization.

11515512861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1279501435 (or 1279501432 counting only the distinct ones).

The product of its digits is 12000, while the sum is 36.

The spelling of 11515512861 in words is "eleven billion, five hundred fifteen million, five hundred twelve thousand, eight hundred sixty-one".