161217500 has 60 divisors (see below), whose sum is σ = 358853880. Its totient is φ = 63336000.

The previous prime is 161217493. The next prime is 161217503. The reversal of 161217500 is 5712161.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161217503) by changing a digit.

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 19 ways as a sum of consecutive naturals, for example, 146954 + ... + 148046.

It is an arithmetic number, because the mean of its divisors is an integer number (5980898).

Almost surely, 2^161217500 is an apocalyptic number.

161217500 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 161217500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179426940).

161217500 is an abundant number, since it is smaller than the sum of its proper divisors (197636380).

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

161217500 is a wasteful number, since it uses less digits than its factorization.

161217500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1176 (or 1159 counting only the distinct ones).

The product of its (nonzero) digits is 420, while the sum is 23.

The square root of 161217500 is about 12697.1453484632. The cubic root of 161217500 is about 544.2570467397.

Adding to 161217500 its reverse (5712161), we get a palindrome (166929661).

The spelling of 161217500 in words is "one hundred sixty-one million, two hundred seventeen thousand, five hundred".