111561661001 has 16 divisors (see below), whose sum is σ = 130208238720. Its totient is φ = 93613660800.

The previous prime is 111561660989. The next prime is 111561661009. The reversal of 111561661001 is 100166165111.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 111561661001 - 2¹⁴ = 111561644617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (111561661009) 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, 823571 + ... + 949416.

It is an arithmetic number, because the mean of its divisors is an integer number (8138014920).

Almost surely, 2^111561661001 is an apocalyptic number.

It is an amenable number.

111561661001 is a deficient number, since it is larger than the sum of its proper divisors (18646577719).

111561661001 is a wasteful number, since it uses less digits than its factorization.

111561661001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1773184.

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

The spelling of 111561661001 in words is "one hundred eleven billion, five hundred sixty-one million, six hundred sixty-one thousand, one".