161855661845 has 16 divisors (see below), whose sum is σ = 208129642560. Its totient is φ = 120399500544.

The previous prime is 161855661833. The next prime is 161855661883. The reversal of 161855661845 is 548166558161.

It is a cyclic number.

It is not a de Polignac number, because 161855661845 - 2¹⁰ = 161855660821 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11463935 + ... + 11478044.

It is an arithmetic number, because the mean of its divisors is an integer number (13008102660).

Almost surely, 2^161855661845 is an apocalyptic number.

It is an amenable number.

161855661845 is a deficient number, since it is larger than the sum of its proper divisors (46273980715).

161855661845 is a wasteful number, since it uses less digits than its factorization.

161855661845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22942084.

The product of its digits is 6912000, while the sum is 56.

The spelling of 161855661845 in words is "one hundred sixty-one billion, eight hundred fifty-five million, six hundred sixty-one thousand, eight hundred forty-five".