1721455855813 has 2 divisors, whose sum is σ = 1721455855814. Its totient is φ = 1721455855812.

The previous prime is 1721455855789. The next prime is 1721455855901. The reversal of 1721455855813 is 3185585541271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1664972154244 + 56483701569 = 1290338^2 + 237663^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721455855813 - 2¹³ = 1721455847621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1721455855013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860727927906 + 860727927907.

It is an arithmetic number, because the mean of its divisors is an integer number (860727927907).

Almost surely, 2^{1721455855813} is an apocalyptic number.

It is an amenable number.

1721455855813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721455855813 is an equidigital number, since it uses as much as digits as its factorization.

1721455855813 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720000, while the sum is 55.

The spelling of 1721455855813 in words is "one trillion, seven hundred twenty-one billion, four hundred fifty-five million, eight hundred fifty-five thousand, eight hundred thirteen".