161858878722 has 90 divisors (see below), whose sum is σ = 368571312747. Its totient is φ = 53090982144.

The previous prime is 161858878717. The next prime is 161858878739. The reversal of 161858878722 is 227878858161.

161858878722 is a `hidden beast` number, since 1 + 618 + 5 + 8 + 8 + 7 + 8 + 7 + 2 + 2 = 666.

161858878722 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 5 ways, for example, as 25638094161 + 136220784561 = 160119^2 + 369081^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=284481.

It is a super-2 number, since 2×161858878722² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161858878722.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 373807818 + ... + 373808250.

Almost surely, 2^161858878722 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161858878722

161858878722 is an abundant number, since it is smaller than the sum of its proper divisors (206712434025).

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

161858878722 is an frugal number, since it uses more digits than its factorization.

161858878722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1026 (or 511 counting only the distinct ones).

The product of its digits is 24084480, while the sum is 63.

The spelling of 161858878722 in words is "one hundred sixty-one billion, eight hundred fifty-eight million, eight hundred seventy-eight thousand, seven hundred twenty-two".