161871220 has 48 divisors (see below), whose sum is σ = 395095680. Its totient is φ = 54555264.

The previous prime is 161871209. The next prime is 161871233. The reversal of 161871220 is 22178161.

161871220 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (28).

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, 1539 + ... + 18058.

It is an arithmetic number, because the mean of its divisors is an integer number (8231160).

Almost surely, 2^161871220 is an apocalyptic number.

161871220 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 161871220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (197547840).

161871220 is an abundant number, since it is smaller than the sum of its proper divisors (233224460).

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

161871220 is a wasteful number, since it uses less digits than its factorization.

161871220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19672 (or 19670 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 28.

The square root of 161871220 is about 12722.8620993863. The cubic root of 161871220 is about 544.9916896861.

The spelling of 161871220 in words is "one hundred sixty-one million, eight hundred seventy-one thousand, two hundred twenty".