726257255221 has 8 divisors (see below), whose sum is σ = 769018296024. Its totient is φ = 683500661760.

The previous prime is 726257255173. The next prime is 726257255233. The reversal of 726257255221 is 122552752627.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 313052559121 + 413204696100 = 559511^2 + 642810^2 .

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

It is not a de Polignac number, because 726257255221 - 2¹³ = 726257247029 is a prime.

It is a super-2 number, since 2×726257255221² (a number of 25 digits) 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 (726257255281) 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, 772660 + ... + 1431613.

It is an arithmetic number, because the mean of its divisors is an integer number (96127287003).

Almost surely, 2^726257255221 is an apocalyptic number.

It is an amenable number.

726257255221 is a deficient number, since it is larger than the sum of its proper divisors (42761040803).

726257255221 is a wasteful number, since it uses less digits than its factorization.

726257255221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2223671.

The product of its digits is 1176000, while the sum is 46.

The spelling of 726257255221 in words is "seven hundred twenty-six billion, two hundred fifty-seven million, two hundred fifty-five thousand, two hundred twenty-one".