721130161 has 8 divisors (see below), whose sum is σ = 759353600. Its totient is φ = 682933680.

The previous prime is 721130149. The next prime is 721130183. The reversal of 721130161 is 161031127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 721130161 - 2¹⁵ = 721097393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721130101) 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 7 ways as a sum of consecutive naturals, for example, 71680 + ... + 81118.

It is an arithmetic number, because the mean of its divisors is an integer number (94919200).

Almost surely, 2^721130161 is an apocalyptic number.

It is an amenable number.

721130161 is a deficient number, since it is larger than the sum of its proper divisors (38223439).

721130161 is a wasteful number, since it uses less digits than its factorization.

721130161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13479.

The product of its (nonzero) digits is 252, while the sum is 22.

The square root of 721130161 is about 26853.8667792927. The cubic root of 721130161 is about 896.7496586825.

Adding to 721130161 its reverse (161031127), we get a palindrome (882161288).

The spelling of 721130161 in words is "seven hundred twenty-one million, one hundred thirty thousand, one hundred sixty-one".