721868489 has 2 divisors, whose sum is σ = 721868490. Its totient is φ = 721868488.

The previous prime is 721868473. The next prime is 721868507. The reversal of 721868489 is 984868127.

It is a happy number.

721868489 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 471975625 + 249892864 = 21725^2 + 15808^2 .

It is a cyclic number.

It is not a de Polignac number, because 721868489 - 2⁴ = 721868473 is a prime.

It is a super-2 number, since 2×721868489² = 1042188230822286242, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721868489.

It is not a weakly prime, because it can be changed into another prime (721868089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360934244 + 360934245.

It is an arithmetic number, because the mean of its divisors is an integer number (360934245).

Almost surely, 2^721868489 is an apocalyptic number.

It is an amenable number.

721868489 is a deficient number, since it is larger than the sum of its proper divisors (1).

721868489 is an equidigital number, since it uses as much as digits as its factorization.

721868489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1548288, while the sum is 53.

The square root of 721868489 is about 26867.6104073287. The cubic root of 721868489 is about 897.0555995443.

The spelling of 721868489 in words is "seven hundred twenty-one million, eight hundred sixty-eight thousand, four hundred eighty-nine".