726991 has 2 divisors, whose sum is σ = 726992. Its totient is φ = 726990.

The previous prime is 726989. The next prime is 727003. The reversal of 726991 is 199627.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 726991 - 2¹ = 726989 is a prime.

Together with 726989, it forms a pair of twin primes.

726991 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (726911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 363495 + 363496.

It is an arithmetic number, because the mean of its divisors is an integer number (363496).

2⁷²⁶⁹⁹¹ is an apocalyptic number.

726991 is a deficient number, since it is larger than the sum of its proper divisors (1).

726991 is an equidigital number, since it uses as much as digits as its factorization.

726991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6804, while the sum is 34.

The square root of 726991 is about 852.6376721680. The cubic root of 726991 is about 89.9172490404.

The spelling of 726991 in words is "seven hundred twenty-six thousand, nine hundred ninety-one".