161998746 has 128 divisors (see below), whose sum is σ = 436617216. Its totient is φ = 38845440.

The previous prime is 161998717. The next prime is 161998747. The reversal of 161998746 is 647899161.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (161998747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 287461 + ... + 288023.

It is an arithmetic number, because the mean of its divisors is an integer number (3411072).

Almost surely, 2^161998746 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161998746, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (218308608).

161998746 is an abundant number, since it is smaller than the sum of its proper divisors (274618470).

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

161998746 is a wasteful number, since it uses less digits than its factorization.

161998746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636.

The product of its digits is 653184, while the sum is 51.

The square root of 161998746 is about 12727.8727994901. The cubic root of 161998746 is about 545.1347712601.

The spelling of 161998746 in words is "one hundred sixty-one million, nine hundred ninety-eight thousand, seven hundred forty-six".