161945980 has 72 divisors (see below), whose sum is σ = 397767888. Its totient is φ = 55222272.

The previous prime is 161945963. The next prime is 161945983. The reversal of 161945980 is 89549161.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161945983) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 251539 + ... + 252181.

It is an arithmetic number, because the mean of its divisors is an integer number (5524554).

Almost surely, 2^161945980 is an apocalyptic number.

161945980 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 161945980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (198883944).

161945980 is an abundant number, since it is smaller than the sum of its proper divisors (235821908).

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

161945980 is a wasteful number, since it uses less digits than its factorization.

161945980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 923 (or 914 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 161945980 is about 12725.7997784029. The cubic root of 161945980 is about 545.0755779933.

The spelling of 161945980 in words is "one hundred sixty-one million, nine hundred forty-five thousand, nine hundred eighty".