726021 has 6 divisors (see below), whose sum is σ = 1048710. Its totient is φ = 484008.

The previous prime is 726013. The next prime is 726023. The reversal of 726021 is 120627.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 509796 + 216225 = 714^2 + 465^2 .

It is not a de Polignac number, because 726021 - 2³ = 726013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 725985 and 726003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (726023) 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 5 ways as a sum of consecutive naturals, for example, 40326 + ... + 40343.

It is an arithmetic number, because the mean of its divisors is an integer number (174785).

2⁷²⁶⁰²¹ is an apocalyptic number.

It is an amenable number.

726021 is a deficient number, since it is larger than the sum of its proper divisors (322689).

726021 is a wasteful number, since it uses less digits than its factorization.

726021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80675 (or 80672 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 726021 is about 852.0686592053. The cubic root of 726021 is about 89.8772400390.

Adding to 726021 its reverse (120627), we get a palindrome (846648).

The spelling of 726021 in words is "seven hundred twenty-six thousand, twenty-one".