1981208959281 has 16 divisors (see below), whose sum is σ = 2935225998720. Its totient is φ = 1320760246320.

The previous prime is 1981208959277. The next prime is 1981208959343. The reversal of 1981208959281 is 1829598021891.

1981208959281 is a `hidden beast` number, since 19 + 8 + 1 + 20 + 8 + 9 + 592 + 8 + 1 = 666.

It is not a de Polignac number, because 1981208959281 - 2² = 1981208959277 is a prime.

It is a super-2 number, since 2×1981208959281² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1981208959481) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 466605 + ... + 2044538.

It is an arithmetic number, because the mean of its divisors is an integer number (183451624920).

Almost surely, 2^{1981208959281} is an apocalyptic number.

It is an amenable number.

1981208959281 is a deficient number, since it is larger than the sum of its proper divisors (954017039439).

1981208959281 is a wasteful number, since it uses less digits than its factorization.

1981208959281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2540373 (or 2540367 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 63.

The spelling of 1981208959281 in words is "one trillion, nine hundred eighty-one billion, two hundred eight million, nine hundred fifty-nine thousand, two hundred eighty-one".