161245220 has 48 divisors (see below), whose sum is σ = 351797040. Its totient is φ = 62006784.

The previous prime is 161245211. The next prime is 161245283. The reversal of 161245220 is 22542161.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 3290596 + 157954624 = 1814^2 + 12568^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 183422 + ... + 184298.

It is an arithmetic number, because the mean of its divisors is an integer number (7329105).

Almost surely, 2^161245220 is an apocalyptic number.

161245220 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 161245220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (175898520).

161245220 is an abundant number, since it is smaller than the sum of its proper divisors (190551820).

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

161245220 is a wasteful number, since it uses less digits than its factorization.

161245220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1232 (or 1230 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 161245220 is about 12698.2368854893. The cubic root of 161245220 is about 544.2882384336.

Adding to 161245220 its reverse (22542161), we get a palindrome (183787381).

The spelling of 161245220 in words is "one hundred sixty-one million, two hundred forty-five thousand, two hundred twenty".