161205891061 has 16 divisors (see below), whose sum is σ = 163420945600. Its totient is φ = 159005887488.

The previous prime is 161205891053. The next prime is 161205891131. The reversal of 161205891061 is 160198502161.

It is a cyclic number.

It is not a de Polignac number, because 161205891061 - 2³ = 161205891053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161205891661) 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, 23833066 + ... + 23839828.

It is an arithmetic number, because the mean of its divisors is an integer number (10213809100).

Almost surely, 2^161205891061 is an apocalyptic number.

It is an amenable number.

161205891061 is a deficient number, since it is larger than the sum of its proper divisors (2215054539).

161205891061 is a wasteful number, since it uses less digits than its factorization.

161205891061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7828.

The product of its (nonzero) digits is 25920, while the sum is 40.

The spelling of 161205891061 in words is "one hundred sixty-one billion, two hundred five million, eight hundred ninety-one thousand, sixty-one".