1081721 has 2 divisors, whose sum is σ = 1081722. Its totient is φ = 1081720.

The previous prime is 1081711. The next prime is 1081723. The reversal of 1081721 is 1271801.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1081600 + 121 = 1040^2 + 11^2 .

It is a cyclic number.

It is not a de Polignac number, because 1081721 - 2⁶ = 1081657 is a prime.

It is a Sophie Germain prime.

Together with 1081723, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1081693 and 1081702.

It is not a weakly prime, because it can be changed into another prime (1081723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 540860 + 540861.

It is an arithmetic number, because the mean of its divisors is an integer number (540861).

2^1081721 is an apocalyptic number.

It is an amenable number.

1081721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1081721 is an equidigital number, since it uses as much as digits as its factorization.

1081721 is an evil number, because the sum of its binary digits is even.

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

The square root of 1081721 is about 1040.0581714500. The cubic root of 1081721 is about 102.6530254453.

The spelling of 1081721 in words is "one million, eighty-one thousand, seven hundred twenty-one".