1981583 has 2 divisors, whose sum is σ = 1981584. Its totient is φ = 1981582.

The previous prime is 1981547. The next prime is 1981589. The reversal of 1981583 is 3851891.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1981589) 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, 990791 + 990792.

It is an arithmetic number, because the mean of its divisors is an integer number (990792).

2^1981583 is an apocalyptic number.

1981583 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981583 is an equidigital number, since it uses as much as digits as its factorization.

1981583 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 35.

The square root of 1981583 is about 1407.6871101207. The cubic root of 1981583 is about 125.6041790366.

The spelling of 1981583 in words is "one million, nine hundred eighty-one thousand, five hundred eighty-three".