721238873 has 2 divisors, whose sum is σ = 721238874. Its totient is φ = 721238872.

The previous prime is 721238809. The next prime is 721238909. The reversal of 721238873 is 378832127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 720546649 + 692224 = 26843^2 + 832^2 .

It is a cyclic number.

It is not a de Polignac number, because 721238873 - 2⁶ = 721238809 is a prime.

It is a super-3 number, since 3×721238873³ (a number of 28 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 721238873.

It is not a weakly prime, because it can be changed into another prime (721238173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360619436 + 360619437.

It is an arithmetic number, because the mean of its divisors is an integer number (360619437).

Almost surely, 2^721238873 is an apocalyptic number.

It is an amenable number.

721238873 is a deficient number, since it is larger than the sum of its proper divisors (1).

721238873 is an equidigital number, since it uses as much as digits as its factorization.

721238873 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 112896, while the sum is 41.

The square root of 721238873 is about 26855.8908435375. The cubic root of 721238873 is about 896.7947187636.

The spelling of 721238873 in words is "seven hundred twenty-one million, two hundred thirty-eight thousand, eight hundred seventy-three".