111201561561 has 16 divisors (see below), whose sum is σ = 151824784320. Its totient is φ = 72358809600.

The previous prime is 111201561539. The next prime is 111201561571. The reversal of 111201561561 is 165165102111.

It is not a de Polignac number, because 111201561561 - 2¹⁰ = 111201560537 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (111201561521) 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, 124140 + ... + 487661.

It is an arithmetic number, because the mean of its divisors is an integer number (9489049020).

Almost surely, 2^111201561561 is an apocalyptic number.

It is an amenable number.

111201561561 is a deficient number, since it is larger than the sum of its proper divisors (40623222759).

111201561561 is a wasteful number, since it uses less digits than its factorization.

111201561561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 613256.

The product of its (nonzero) digits is 1800, while the sum is 30.

Adding to 111201561561 its reverse (165165102111), we get a palindrome (276366663672).

The spelling of 111201561561 in words is "one hundred eleven billion, two hundred one million, five hundred sixty-one thousand, five hundred sixty-one".