165611111601 has 32 divisors (see below), whose sum is σ = 239423063040. Its totient is φ = 101220197184.

The previous prime is 165611111591. The next prime is 165611111609. The reversal of 165611111601 is 106111116561.

It is not a de Polignac number, because 165611111601 - 2⁵ = 165611111569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165611111609) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8346270 + ... + 8366088.

It is an arithmetic number, because the mean of its divisors is an integer number (7481970720).

Almost surely, 2^165611111601 is an apocalyptic number.

It is an amenable number.

165611111601 is a deficient number, since it is larger than the sum of its proper divisors (73811951439).

165611111601 is a wasteful number, since it uses less digits than its factorization.

165611111601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21285.

The product of its (nonzero) digits is 1080, while the sum is 30.

The spelling of 165611111601 in words is "one hundred sixty-five billion, six hundred eleven million, one hundred eleven thousand, six hundred one".