1721081 has 2 divisors, whose sum is σ = 1721082. Its totient is φ = 1721080.

The previous prime is 1721023. The next prime is 1721123. The reversal of 1721081 is 1801271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1401856 + 319225 = 1184^2 + 565^2 .

It is a cyclic number.

It is not a de Polignac number, because 1721081 - 2¹⁰ = 1720057 is a prime.

It is a super-2 number, since 2×1721081² = 5924239617122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1721011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860540 + 860541.

It is an arithmetic number, because the mean of its divisors is an integer number (860541).

2^1721081 is an apocalyptic number.

It is an amenable number.

1721081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1721081 is an equidigital number, since it uses as much as digits as its factorization.

1721081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 1721081 is about 1311.8997675127. The cubic root of 1721081 is about 119.8396237205.

The spelling of 1721081 in words is "one million, seven hundred twenty-one thousand, eighty-one".