1081681 has 2 divisors, whose sum is σ = 1081682. Its totient is φ = 1081680.

The previous prime is 1081679. The next prime is 1081687. The reversal of 1081681 is 1861801.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1081600 + 81 = 1040^2 + 9^2 .

It is a cyclic number.

It is not a de Polignac number, because 1081681 - 2¹ = 1081679 is a prime.

It is a super-2 number, since 2×1081681² = 2340067571522, which contains 22 as substring.

Together with 1081679, it forms a pair of twin primes.

1081681 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1081687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 540840 + 540841.

It is an arithmetic number, because the mean of its divisors is an integer number (540841).

2^1081681 is an apocalyptic number.

It is an amenable number.

1081681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1081681 is an equidigital number, since it uses as much as digits as its factorization.

1081681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 25.

The square root of 1081681 is about 1040.0389415786. The cubic root of 1081681 is about 102.6517601247.

It can be divided in two parts, 10816 and 81, that multiplied together give a square (876096 = 936²).

The spelling of 1081681 in words is "one million, eighty-one thousand, six hundred eighty-one".