161808840 has 224 divisors, whose sum is σ = 566611200. Its totient is φ = 41523840.

The previous prime is 161808833. The next prime is 161808859. The reversal of 161808840 is 48808161.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 161808795 and 161808804.

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 903871 + ... + 904049.

Almost surely, 2^161808840 is an apocalyptic number.

161808840 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 161808840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (283305600).

161808840 is an abundant number, since it is smaller than the sum of its proper divisors (404802360).

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

161808840 is a wasteful number, since it uses less digits than its factorization.

161808840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239 (or 220 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 161808840 is about 12720.4103707388. The cubic root of 161808840 is about 544.9216732257.

The spelling of 161808840 in words is "one hundred sixty-one million, eight hundred eight thousand, eight hundred forty".