11661560561511 has 24 divisors (see below), whose sum is σ = 19254686216480. Its totient is φ = 6662414094336.

The previous prime is 11661560561447. The next prime is 11661560561551. The reversal of 11661560561511 is 11516506516611.

11661560561511 is a `hidden beast` number, since 1 + 1 + 6 + 6 + 15 + 6 + 0 + 5 + 615 + 11 = 666.

It is not a de Polignac number, because 11661560561511 - 2⁶ = 11661560561447 is a prime.

It is a super-2 number, since 2×11661560561511² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11661560561551) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18221806 + ... + 18850923.

Almost surely, 2^{11661560561511} is an apocalyptic number.

11661560561511 is a deficient number, since it is larger than the sum of its proper divisors (7593125654969).

11661560561511 is a wasteful number, since it uses less digits than its factorization.

11661560561511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37077735 (or 37077732 counting only the distinct ones).

The product of its (nonzero) digits is 162000, while the sum is 45.

The spelling of 11661560561511 in words is "eleven trillion, six hundred sixty-one billion, five hundred sixty million, five hundred sixty-one thousand, five hundred eleven".