161000161920 has 1920 divisors, whose sum is σ = 702510589440. Its totient is φ = 34918760448.

The previous prime is 161000161919. The next prime is 161000161961. The reversal of 161000161920 is 29161000161.

161000161920 is a `hidden beast` number, since 1 + 610 + 0 + 0 + 16 + 19 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (1920).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 3425535337 + ... + 3425535383.

It is an arithmetic number, because the mean of its divisors is an integer number (365890932).

Almost surely, 2^161000161920 is an apocalyptic number.

161000161920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161000161920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (351255294720).

161000161920 is an abundant number, since it is smaller than the sum of its proper divisors (541510427520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161000161920 is a wasteful number, since it uses less digits than its factorization.

161000161920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The spelling of 161000161920 in words is "one hundred sixty-one billion, one hundred sixty-one thousand, nine hundred twenty".