161820120 has 256 divisors, whose sum is σ = 615444480. Its totient is φ = 33062400.

The previous prime is 161820119. The next prime is 161820121. The reversal of 161820120 is 21028161.

161820120 is digitally balanced in base 2, 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 (161820119) and next prime (161820121).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161820121) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 766815 + ... + 767025.

It is an arithmetic number, because the mean of its divisors is an integer number (2404080).

Almost surely, 2^161820120 is an apocalyptic number.

161820120 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 161820120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (307722240).

161820120 is an abundant number, since it is smaller than the sum of its proper divisors (453624360).

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

161820120 is a wasteful number, since it uses less digits than its factorization.

161820120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 161820120 is about 12720.8537449339. The cubic root of 161820120 is about 544.9343354380.

Adding to 161820120 its reverse (21028161), we get a palindrome (182848281).

The spelling of 161820120 in words is "one hundred sixty-one million, eight hundred twenty thousand, one hundred twenty".