721868507 has 2 divisors, whose sum is σ = 721868508. Its totient is φ = 721868506.

The previous prime is 721868489. The next prime is 721868531. The reversal of 721868507 is 705868127.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 721868507 - 2¹⁰ = 721867483 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (721868597) 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 as a sum of consecutive naturals, namely, 360934253 + 360934254.

It is an arithmetic number, because the mean of its divisors is an integer number (360934254).

Almost surely, 2^721868507 is an apocalyptic number.

721868507 is a deficient number, since it is larger than the sum of its proper divisors (1).

721868507 is an equidigital number, since it uses as much as digits as its factorization.

721868507 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 188160, while the sum is 44.

The square root of 721868507 is about 26867.6107423046. The cubic root of 721868507 is about 897.0556070004.

The spelling of 721868507 in words is "seven hundred twenty-one million, eight hundred sixty-eight thousand, five hundred seven".