721810849 has 2 divisors, whose sum is σ = 721810850. Its totient is φ = 721810848.

The previous prime is 721810813. The next prime is 721810861. The reversal of 721810849 is 948018127.

It is a happy number.

721810849 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 694059025 + 27751824 = 26345^2 + 5268^2 .

It is a cyclic number.

It is not a de Polignac number, because 721810849 - 2⁷ = 721810721 is a prime.

It is not a weakly prime, because it can be changed into another prime (721810889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360905424 + 360905425.

It is an arithmetic number, because the mean of its divisors is an integer number (360905425).

Almost surely, 2^721810849 is an apocalyptic number.

It is an amenable number.

721810849 is a deficient number, since it is larger than the sum of its proper divisors (1).

721810849 is an equidigital number, since it uses as much as digits as its factorization.

721810849 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 40.

The square root of 721810849 is about 26866.5377188800. The cubic root of 721810849 is about 897.0317227755.

The spelling of 721810849 in words is "seven hundred twenty-one million, eight hundred ten thousand, eight hundred forty-nine".