161806840 has 128 divisors (see below), whose sum is σ = 416586240. Its totient is φ = 56111616.

The previous prime is 161806837. The next prime is 161806889. The reversal of 161806840 is 48608161.

It is a junction number, because it is equal to n+sod(n) for n = 161806796 and 161806805.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 992599 + ... + 992761.

It is an arithmetic number, because the mean of its divisors is an integer number (3254580).

Almost surely, 2^161806840 is an apocalyptic number.

161806840 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 161806840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (208293120).

161806840 is an abundant number, since it is smaller than the sum of its proper divisors (254779400).

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

161806840 is a wasteful number, since it uses less digits than its factorization.

161806840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293 (or 289 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 161806840 is about 12720.3317566799. The cubic root of 161806840 is about 544.9194280912.

The spelling of 161806840 in words is "one hundred sixty-one million, eight hundred six thousand, eight hundred forty".