161819840 has 112 divisors (see below), whose sum is σ = 474341952. Its totient is φ = 51204096.

The previous prime is 161819837. The next prime is 161819843. The reversal of 161819840 is 48918161.

161819840 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (161819837) and next prime (161819843).

It is a tau number, because it is divible by the number of its divisors (112).

It is a junction number, because it is equal to n+sod(n) for n = 161819794 and 161819803.

It is not an unprimeable number, because it can be changed into a prime (161819843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26342 + ... + 31898.

It is an arithmetic number, because the mean of its divisors is an integer number (4235196).

Almost surely, 2^161819840 is an apocalyptic number.

161819840 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 161819840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (237170976).

161819840 is an abundant number, since it is smaller than the sum of its proper divisors (312522112).

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

161819840 is a wasteful number, since it uses less digits than its factorization.

161819840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5594 (or 5584 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 38.

The square root of 161819840 is about 12720.8427393786. The cubic root of 161819840 is about 544.9340211349.

The spelling of 161819840 in words is "one hundred sixty-one million, eight hundred nineteen thousand, eight hundred forty".