721189 has 8 divisors (see below), whose sum is σ = 829440. Its totient is φ = 614256.

The previous prime is 721181. The next prime is 721199. The reversal of 721189 is 981127.

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 721189 - 2³ = 721181 is a prime.

It is a super-2 number, since 2×721189² = 1040227147442, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1692 + ... + 2074.

It is an arithmetic number, because the mean of its divisors is an integer number (103680).

2⁷²¹¹⁸⁹ is an apocalyptic number.

It is an amenable number.

721189 is a deficient number, since it is larger than the sum of its proper divisors (108251).

721189 is a wasteful number, since it uses less digits than its factorization.

721189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 659.

The product of its digits is 1008, while the sum is 28.

The square root of 721189 is about 849.2284733804. The cubic root of 721189 is about 89.6774047446.

It can be divided in two parts, 72118 and 9, that added together give a palindrome (72127).

The spelling of 721189 in words is "seven hundred twenty-one thousand, one hundred eighty-nine".