111561661100 has 72 divisors (see below), whose sum is σ = 243055224720. Its totient is φ = 44446842880.

The previous prime is 111561661097. The next prime is 111561661103. The reversal of 111561661100 is 1166165111.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (111561661097) and next prime (111561661103).

It is not an unprimeable number, because it can be changed into a prime (111561661103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49736579 + ... + 49738821.

It is an arithmetic number, because the mean of its divisors is an integer number (3375767010).

Almost surely, 2^111561661100 is an apocalyptic number.

111561661100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

111561661100 is an abundant number, since it is smaller than the sum of its proper divisors (131493563620).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

111561661100 is a wasteful number, since it uses less digits than its factorization.

111561661100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4019 (or 4012 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 29.

The spelling of 111561661100 in words is "one hundred eleven billion, five hundred sixty-one million, six hundred sixty-one thousand, one hundred".