1720818817 has 2 divisors, whose sum is σ = 1720818818. Its totient is φ = 1720818816.

The previous prime is 1720818793. The next prime is 1720818857. The reversal of 1720818817 is 7188180271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1047104881 + 673713936 = 32359^2 + 25956^2 .

It is a cyclic number.

It is not a de Polignac number, because 1720818817 - 2²⁷ = 1586601089 is a prime.

It is a super-2 number, since 2×1720818817² = 5922434801882558978, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1720818857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860409408 + 860409409.

It is an arithmetic number, because the mean of its divisors is an integer number (860409409).

Almost surely, 2^1720818817 is an apocalyptic number.

It is an amenable number.

1720818817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720818817 is an equidigital number, since it uses as much as digits as its factorization.

1720818817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50176, while the sum is 43.

The square root of 1720818817 is about 41482.7532475847. The cubic root of 1720818817 is about 1198.3353810579.

The spelling of 1720818817 in words is "one billion, seven hundred twenty million, eight hundred eighteen thousand, eight hundred seventeen".