1981133132285 has 4 divisors (see below), whose sum is σ = 2377359758748. Its totient is φ = 1584906505824.

The previous prime is 1981133132273. The next prime is 1981133132287. The reversal of 1981133132285 is 5822313311891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1178010671044 + 803122461241 = 1085362^2 + 896171^2 .

It is a cyclic number.

It is not a de Polignac number, because 1981133132285 - 2¹⁶ = 1981133066749 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981133132287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198113313224 + ... + 198113313233.

It is an arithmetic number, because the mean of its divisors is an integer number (594339939687).

Almost surely, 2^{1981133132285} is an apocalyptic number.

It is an amenable number.

1981133132285 is a deficient number, since it is larger than the sum of its proper divisors (396226626463).

1981133132285 is an equidigital number, since it uses as much as digits as its factorization.

1981133132285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396226626462.

The product of its digits is 311040, while the sum is 47.

The spelling of 1981133132285 in words is "one trillion, nine hundred eighty-one billion, one hundred thirty-three million, one hundred thirty-two thousand, two hundred eighty-five".