1981933673449 has 2 divisors, whose sum is σ = 1981933673450. Its totient is φ = 1981933673448.

The previous prime is 1981933673441. The next prime is 1981933673479. The reversal of 1981933673449 is 9443763391891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1586503989225 + 395429684224 = 1259565^2 + 628832^2 .

It is an emirp because it is prime and its reverse (9443763391891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1981933673449 - 2³ = 1981933673441 is a prime.

It is a super-2 number, since 2×1981933673449² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1981933673441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990966836724 + 990966836725.

It is an arithmetic number, because the mean of its divisors is an integer number (990966836725).

Almost surely, 2^{1981933673449} is an apocalyptic number.

It is an amenable number.

1981933673449 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981933673449 is an equidigital number, since it uses as much as digits as its factorization.

1981933673449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 105815808, while the sum is 67.

The spelling of 1981933673449 in words is "one trillion, nine hundred eighty-one billion, nine hundred thirty-three million, six hundred seventy-three thousand, four hundred forty-nine".