1981099 has 2 divisors, whose sum is σ = 1981100. Its totient is φ = 1981098.

The previous prime is 1981093. The next prime is 1981141. The reversal of 1981099 is 9901891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1981099 - 2¹¹ = 1979051 is a prime.

It is a Chen prime.

It is a plaindrome in base 11.

It is not a weakly prime, because it can be changed into another prime (1981093) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990549 + 990550.

It is an arithmetic number, because the mean of its divisors is an integer number (990550).

2^1981099 is an apocalyptic number.

1981099 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981099 is an equidigital number, since it uses as much as digits as its factorization.

1981099 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 37.

The square root of 1981099 is about 1407.5151864190. The cubic root of 1981099 is about 125.5939519651.

It can be divided in two parts, 19810 and 99, that multiplied together give a triangular number (1961190 = T₁₉₈₀).

The spelling of 1981099 in words is "one million, nine hundred eighty-one thousand, ninety-nine".