2121000020981 has 2 divisors, whose sum is σ = 2121000020982. Its totient is φ = 2121000020980.

The previous prime is 2121000020947. The next prime is 2121000021017. The reversal of 2121000020981 is 1890200001212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1733567222500 + 387432798481 = 1316650^2 + 622441^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121000020981 - 2³⁰ = 2119926279157 is a prime.

It is a super-2 number, since 2×2121000020981² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2121000020981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121000020081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060500010490 + 1060500010491.

It is an arithmetic number, because the mean of its divisors is an integer number (1060500010491).

Almost surely, 2^{2121000020981} is an apocalyptic number.

It is an amenable number.

2121000020981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121000020981 is an equidigital number, since it uses as much as digits as its factorization.

2121000020981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 26.

The spelling of 2121000020981 in words is "two trillion, one hundred twenty-one billion, twenty thousand, nine hundred eighty-one".