210213311981 has 2 divisors, whose sum is σ = 210213311982. Its totient is φ = 210213311980.

The previous prime is 210213311941. The next prime is 210213312019. The reversal of 210213311981 is 189113312012.

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., 110379430756 + 99833881225 = 332234^2 + 315965^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-210213311981 is a prime.

It is a super-2 number, since 2×210213311981² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (210213311941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105106655990 + 105106655991.

It is an arithmetic number, because the mean of its divisors is an integer number (105106655991).

Almost surely, 2^210213311981 is an apocalyptic number.

It is an amenable number.

210213311981 is a deficient number, since it is larger than the sum of its proper divisors (1).

210213311981 is an equidigital number, since it uses as much as digits as its factorization.

210213311981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 32.

Adding to 210213311981 its reverse (189113312012), we get a palindrome (399326623993).

The spelling of 210213311981 in words is "two hundred ten billion, two hundred thirteen million, three hundred eleven thousand, nine hundred eighty-one".