211211020019981 has 2 divisors, whose sum is σ = 211211020019982. Its totient is φ = 211211020019980.

The previous prime is 211211020019959. The next prime is 211211020020001. The reversal of 211211020019981 is 189910020112112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 194252066504356 + 16958953515625 = 13937434^2 + 4118125^2 .

It is a cyclic number.

It is not a de Polignac number, because 211211020019981 - 2⁴² = 206812973508877 is a prime.

It is a super-2 number, since 2×211211020019981² (a number of 29 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211211020019921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105605510009990 + 105605510009991.

It is an arithmetic number, because the mean of its divisors is an integer number (105605510009991).

Almost surely, 2^{211211020019981} is an apocalyptic number.

It is an amenable number.

211211020019981 is a deficient number, since it is larger than the sum of its proper divisors (1).

211211020019981 is an equidigital number, since it uses as much as digits as its factorization.

211211020019981 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 38.

The spelling of 211211020019981 in words is "two hundred eleven trillion, two hundred eleven billion, twenty million, nineteen thousand, nine hundred eighty-one".