161812728 has 384 divisors, whose sum is σ = 603832320. Its totient is φ = 39346560.

The previous prime is 161812727. The next prime is 161812753. The reversal of 161812728 is 827218161.

161812728 is a `hidden beast` number, since 1 + 618 + 12 + 7 + 28 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 161812692 and 161812701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161812727) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3442801 + ... + 3442847.

It is an arithmetic number, because the mean of its divisors is an integer number (1572480).

Almost surely, 2^161812728 is an apocalyptic number.

161812728 is a gapful number since it is divisible by the number (18) 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 161812728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (301916160).

161812728 is an abundant number, since it is smaller than the sum of its proper divisors (442019592).

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

161812728 is a wasteful number, since it uses less digits than its factorization.

161812728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 93 counting only the distinct ones).

The product of its digits is 10752, while the sum is 36.

The square root of 161812728 is about 12720.5631950791. The cubic root of 161812728 is about 544.9260377143.

The spelling of 161812728 in words is "one hundred sixty-one million, eight hundred twelve thousand, seven hundred twenty-eight".