1081781 has 2 divisors, whose sum is σ = 1081782. Its totient is φ = 1081780.

The previous prime is 1081777. The next prime is 1081789. The reversal of 1081781 is 1871801.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 970225 + 111556 = 985^2 + 334^2 .

It is a cyclic number.

It is not a de Polignac number, because 1081781 - 2² = 1081777 is a prime.

It is a super-2 number, since 2×1081781² = 2340500263922, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1081781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1081789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 540890 + 540891.

It is an arithmetic number, because the mean of its divisors is an integer number (540891).

2^1081781 is an apocalyptic number.

It is an amenable number.

1081781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1081781 is an equidigital number, since it uses as much as digits as its factorization.

1081781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 26.

The square root of 1081781 is about 1040.0870155905. The cubic root of 1081781 is about 102.6549233678.

The spelling of 1081781 in words is "one million, eighty-one thousand, seven hundred eighty-one".