721161 has 12 divisors (see below), whose sum is σ = 1190592. Its totient is φ = 412056.

The previous prime is 721159. The next prime is 721163. The reversal of 721161 is 161127.

It is an interprime number because it is at equal distance from previous prime (721159) and next prime (721163).

It is not a de Polignac number, because 721161 - 2¹ = 721159 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721161.

It is not an unprimeable number, because it can be changed into a prime (721163) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5661 + ... + 5786.

It is an arithmetic number, because the mean of its divisors is an integer number (99216).

2⁷²¹¹⁶¹ is an apocalyptic number.

It is an amenable number.

721161 is a deficient number, since it is larger than the sum of its proper divisors (469431).

721161 is a wasteful number, since it uses less digits than its factorization.

721161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11460 (or 11457 counting only the distinct ones).

The product of its digits is 84, while the sum is 18.

The square root of 721161 is about 849.2119876686. The cubic root of 721161 is about 89.6762441612.

Adding to 721161 its reverse (161127), we get a palindrome (882288).

The spelling of 721161 in words is "seven hundred twenty-one thousand, one hundred sixty-one".