201211201201981 has 2 divisors, whose sum is σ = 201211201201982. Its totient is φ = 201211201201980.

The previous prime is 201211201201961. The next prime is 201211201201993. The reversal of 201211201201981 is 189102102112102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152983107025956 + 48228094176025 = 12368634^2 + 6944645^2 .

It is a cyclic number.

It is not a de Polignac number, because 201211201201981 - 2⁷ = 201211201201853 is a prime.

It is a super-2 number, since 2×201211201201981² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201211201201961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100605600600990 + 100605600600991.

It is an arithmetic number, because the mean of its divisors is an integer number (100605600600991).

Almost surely, 2^{201211201201981} is an apocalyptic number.

It is an amenable number.

201211201201981 is a deficient number, since it is larger than the sum of its proper divisors (1).

201211201201981 is an equidigital number, since it uses as much as digits as its factorization.

201211201201981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 31.

The spelling of 201211201201981 in words is "two hundred one trillion, two hundred eleven billion, two hundred one million, two hundred one thousand, nine hundred eighty-one".