161909414991 has 12 divisors (see below), whose sum is σ = 235056310632. Its totient is φ = 107391692016.

The previous prime is 161909414951. The next prime is 161909414999. The reversal of 161909414991 is 199414909161.

161909414991 is a `hidden beast` number, since 1 + 61 + 9 + 0 + 94 + 1 + 499 + 1 = 666.

It is not a de Polignac number, because 161909414991 - 2¹⁷ = 161909283919 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161909414999) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45657961 + ... + 45661506.

It is an arithmetic number, because the mean of its divisors is an integer number (19588025886).

Almost surely, 2^161909414991 is an apocalyptic number.

161909414991 is a deficient number, since it is larger than the sum of its proper divisors (73146895641).

161909414991 is a wasteful number, since it uses less digits than its factorization.

161909414991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91319670 (or 91319667 counting only the distinct ones).

The product of its (nonzero) digits is 629856, while the sum is 54.

The spelling of 161909414991 in words is "one hundred sixty-one billion, nine hundred nine million, four hundred fourteen thousand, nine hundred ninety-one".