161120720 has 20 divisors (see below), whose sum is σ = 374605860. Its totient is φ = 64448256.

The previous prime is 161120717. The next prime is 161120731. The reversal of 161120720 is 27021161.

It can be written as a sum of positive squares in 2 ways, for example, as 55771024 + 105349696 = 7468^2 + 10264^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 161120692 and 161120701.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 1006925 + ... + 1007084.

It is an arithmetic number, because the mean of its divisors is an integer number (18730293).

Almost surely, 2^161120720 is an apocalyptic number.

161120720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161120720 is an abundant number, since it is smaller than the sum of its proper divisors (213485140).

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

161120720 is a wasteful number, since it uses less digits than its factorization.

161120720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2014022 (or 2014016 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 161120720 is about 12693.3336834734. Note that the first 3 decimals coincide. The cubic root of 161120720 is about 544.1481178278.

Adding to 161120720 its reverse (27021161), we get a palindrome (188141881).

The spelling of 161120720 in words is "one hundred sixty-one million, one hundred twenty thousand, seven hundred twenty".