1981055749 has 2 divisors, whose sum is σ = 1981055750. Its totient is φ = 1981055748.

The previous prime is 1981055737. The next prime is 1981055777. The reversal of 1981055749 is 9475501891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1376781025 + 604274724 = 37105^2 + 24582^2 .

It is an emirp because it is prime and its reverse (9475501891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1981055749 - 2⁷ = 1981055621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1981055719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990527874 + 990527875.

It is an arithmetic number, because the mean of its divisors is an integer number (990527875).

Almost surely, 2^1981055749 is an apocalyptic number.

It is an amenable number.

1981055749 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981055749 is an equidigital number, since it uses as much as digits as its factorization.

1981055749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 453600, while the sum is 49.

The square root of 1981055749 is about 44509.0524388017. The cubic root of 1981055749 is about 1255.9303797688.

The spelling of 1981055749 in words is "one billion, nine hundred eighty-one million, fifty-five thousand, seven hundred forty-nine".