721728223 has 2 divisors, whose sum is σ = 721728224. Its totient is φ = 721728222.

The previous prime is 721728197. The next prime is 721728257. The reversal of 721728223 is 322827127.

It is a happy number.

It is an a-pointer prime, because the next prime (721728257) can be obtained adding 721728223 to its sum of digits (34).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 721728223 - 2¹³ = 721720031 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721728283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360864111 + 360864112.

It is an arithmetic number, because the mean of its divisors is an integer number (360864112).

Almost surely, 2^721728223 is an apocalyptic number.

721728223 is a deficient number, since it is larger than the sum of its proper divisors (1).

721728223 is an equidigital number, since it uses as much as digits as its factorization.

721728223 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18816, while the sum is 34.

The square root of 721728223 is about 26864.9999627768. Note that the first 4 decimals coincide. The cubic root of 721728223 is about 896.9974935996.

The spelling of 721728223 in words is "seven hundred twenty-one million, seven hundred twenty-eight thousand, two hundred twenty-three".