2001220009981 has 2 divisors, whose sum is σ = 2001220009982. Its totient is φ = 2001220009980.

The previous prime is 2001220009969. The next prime is 2001220010033. The reversal of 2001220009981 is 1899000221002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1995311628025 + 5908381956 = 1412555^2 + 76866^2 .

It is a cyclic number.

It is not a de Polignac number, because 2001220009981 - 2³³ = 1992630075389 is a prime.

It is a super-2 number, since 2×2001220009981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2001220039981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000610004990 + 1000610004991.

It is an arithmetic number, because the mean of its divisors is an integer number (1000610004991).

Almost surely, 2^{2001220009981} is an apocalyptic number.

It is an amenable number.

2001220009981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001220009981 is an equidigital number, since it uses as much as digits as its factorization.

2001220009981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 34.

The spelling of 2001220009981 in words is "two trillion, one billion, two hundred twenty million, nine thousand, nine hundred eighty-one".