2131203221981 has 2 divisors, whose sum is σ = 2131203221982. Its totient is φ = 2131203221980.

The previous prime is 2131203221963. The next prime is 2131203222107. The reversal of 2131203221981 is 1891223021312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1873794125956 + 257409096025 = 1368866^2 + 507355^2 .

It is a cyclic number.

It is not a de Polignac number, because 2131203221981 - 2¹⁰ = 2131203220957 is a prime.

It is a super-2 number, since 2×2131203221981² (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 (2131203221281) 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 as a sum of consecutive naturals, namely, 1065601610990 + 1065601610991.

It is an arithmetic number, because the mean of its divisors is an integer number (1065601610991).

Almost surely, 2^{2131203221981} is an apocalyptic number.

It is an amenable number.

2131203221981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2131203221981 is an equidigital number, since it uses as much as digits as its factorization.

2131203221981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 35.

The spelling of 2131203221981 in words is "two trillion, one hundred thirty-one billion, two hundred three million, two hundred twenty-one thousand, nine hundred eighty-one".