111405661 has 16 divisors (see below), whose sum is σ = 117504000. Its totient is φ = 105494400.

The previous prime is 111405659. The next prime is 111405673. The reversal of 111405661 is 166504111.

It is a cyclic number.

It is not a de Polignac number, because 111405661 - 2¹ = 111405659 is a prime.

It is a super-2 number, since 2×111405661² = 24822442605693842, which 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 (111405611) 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, 410956 + ... + 411226.

It is an arithmetic number, because the mean of its divisors is an integer number (7344000).

Almost surely, 2^111405661 is an apocalyptic number.

It is an amenable number.

111405661 is a deficient number, since it is larger than the sum of its proper divisors (6098339).

111405661 is a wasteful number, since it uses less digits than its factorization.

111405661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 111405661 is about 10554.8880145646. Note that the first 3 decimals coincide. The cubic root of 111405661 is about 481.1742963845.

Adding to 111405661 its reverse (166504111), we get a palindrome (277909772).

The spelling of 111405661 in words is "one hundred eleven million, four hundred five thousand, six hundred sixty-one".