1721408813 has 2 divisors, whose sum is σ = 1721408814. Its totient is φ = 1721408812.

The previous prime is 1721408789. The next prime is 1721408929. The reversal of 1721408813 is 3188041271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 868009444 + 853399369 = 29462^2 + 29213^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721408813 - 2⁶ = 1721408749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721408413) 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, 860704406 + 860704407.

It is an arithmetic number, because the mean of its divisors is an integer number (860704407).

Almost surely, 2^1721408813 is an apocalyptic number.

It is an amenable number.

1721408813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721408813 is an equidigital number, since it uses as much as digits as its factorization.

1721408813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10752, while the sum is 35.

The square root of 1721408813 is about 41489.8639790491. The cubic root of 1721408813 is about 1198.4723182509.

The spelling of 1721408813 in words is "one billion, seven hundred twenty-one million, four hundred eight thousand, eight hundred thirteen".