721337 has 2 divisors, whose sum is σ = 721338. Its totient is φ = 721336.

The previous prime is 721333. The next prime is 721351. The reversal of 721337 is 733127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 583696 + 137641 = 764^2 + 371^2 .

It is an emirp because it is prime and its reverse (733127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721337 - 2² = 721333 is a prime.

It is a Chen prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (721333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360668 + 360669.

It is an arithmetic number, because the mean of its divisors is an integer number (360669).

2⁷²¹³³⁷ is an apocalyptic number.

It is an amenable number.

721337 is a deficient number, since it is larger than the sum of its proper divisors (1).

721337 is an equidigital number, since it uses as much as digits as its factorization.

721337 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 882, while the sum is 23.

The square root of 721337 is about 849.3156068270. The cubic root of 721337 is about 89.6835387576.

The spelling of 721337 in words is "seven hundred twenty-one thousand, three hundred thirty-seven".