161731098 has 48 divisors (see below), whose sum is σ = 374775336. Its totient is φ = 50227200.

The previous prime is 161731093. The next prime is 161731109. The reversal of 161731098 is 890137161.

161731098 is a `hidden beast` number, since 1 + 617 + 31 + 0 + 9 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 143352729 + 18378369 = 11973^2 + 4287^2 .

It is not an unprimeable number, because it can be changed into a prime (161731093) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28290 + ... + 33522.

Almost surely, 2^161731098 is an apocalyptic number.

161731098 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161731098, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (187387668).

161731098 is an abundant number, since it is smaller than the sum of its proper divisors (213044238).

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

161731098 is a wasteful number, since it uses less digits than its factorization.

161731098 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5359 (or 5356 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 161731098 is about 12717.3542059660. The cubic root of 161731098 is about 544.8343889812.

It can be divided in two parts, 16173 and 1098, that added together give a palindrome (17271).

The spelling of 161731098 in words is "one hundred sixty-one million, seven hundred thirty-one thousand, ninety-eight".