11661020111 has 12 divisors (see below), whose sum is σ = 12632077152. Its totient is φ = 10759709376.

The previous prime is 11661020101. The next prime is 11661020167. The reversal of 11661020111 is 11102016611.

It is a happy number.

It is not a de Polignac number, because 11661020111 - 2¹⁴ = 11661003727 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 (11661020101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 456890 + ... + 481736.

It is an arithmetic number, because the mean of its divisors is an integer number (1052673096).

Almost surely, 2^11661020111 is an apocalyptic number.

11661020111 is a deficient number, since it is larger than the sum of its proper divisors (971057041).

11661020111 is a wasteful number, since it uses less digits than its factorization.

11661020111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27650 (or 27637 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 20.

Adding to 11661020111 its reverse (11102016611), we get a palindrome (22763036722).

The spelling of 11661020111 in words is "eleven billion, six hundred sixty-one million, twenty thousand, one hundred eleven".