723721 has 2 divisors, whose sum is σ = 723722. Its totient is φ = 723720.

The previous prime is 723661. The next prime is 723727. The reversal of 723721 is 127327.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 404496 + 319225 = 636^2 + 565^2 .

It is a cyclic number.

It is not a de Polignac number, because 723721 - 2⁹ = 723209 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 723692 and 723701.

It is not a weakly prime, because it can be changed into another prime (723727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 361860 + 361861.

It is an arithmetic number, because the mean of its divisors is an integer number (361861).

2⁷²³⁷²¹ is an apocalyptic number.

It is an amenable number.

723721 is a deficient number, since it is larger than the sum of its proper divisors (1).

723721 is an equidigital number, since it uses as much as digits as its factorization.

723721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 588, while the sum is 22.

The square root of 723721 is about 850.7179321021. The cubic root of 723721 is about 89.7822306992.

It can be divided in two parts, 723 and 721, that added together give a square (1444 = 38²).

The spelling of 723721 in words is "seven hundred twenty-three thousand, seven hundred twenty-one", and thus it is an iban number.