1981949 has 2 divisors, whose sum is σ = 1981950. Its totient is φ = 1981948.

The previous prime is 1981939. The next prime is 1981963. The reversal of 1981949 is 9491891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1836025 + 145924 = 1355^2 + 382^2 .

It is an emirp because it is prime and its reverse (9491891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1981949 - 2¹⁶ = 1916413 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1981919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990974 + 990975.

It is an arithmetic number, because the mean of its divisors is an integer number (990975).

2^1981949 is an apocalyptic number.

It is an amenable number.

1981949 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981949 is an equidigital number, since it uses as much as digits as its factorization.

1981949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 41.

The square root of 1981949 is about 1407.8171045985. The cubic root of 1981949 is about 125.6119116254.

The spelling of 1981949 in words is "one million, nine hundred eighty-one thousand, nine hundred forty-nine".