1981081 has 2 divisors, whose sum is σ = 1981082. Its totient is φ = 1981080.

The previous prime is 1981037. The next prime is 1981093. The reversal of 1981081 is 1801891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1974025 + 7056 = 1405^2 + 84^2 .

It is a cyclic number.

It is not a de Polignac number, because 1981081 - 2¹³ = 1972889 is a prime.

It is a super-2 number, since 2×1981081² = 7849363857122, which contains 22 as substring.

It is an Ulam number.

1981081 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1981181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990540 + 990541.

It is an arithmetic number, because the mean of its divisors is an integer number (990541).

2^1981081 is an apocalyptic number.

It is an amenable number.

1981081 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981081 is an equidigital number, since it uses as much as digits as its factorization.

1981081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 28.

The square root of 1981081 is about 1407.5087921573. The cubic root of 1981081 is about 125.5935715874.

It can be divided in two parts, 19810 and 81, that added together give a palindrome (19891).

The spelling of 1981081 in words is "one million, nine hundred eighty-one thousand, eighty-one".