505030211981 has 2 divisors, whose sum is σ = 505030211982. Its totient is φ = 505030211980.

The previous prime is 505030211921. The next prime is 505030212019. The reversal of 505030211981 is 189112030505.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 504739202500 + 291009481 = 710450^2 + 17059^2 .

It is a cyclic number.

It is not a de Polignac number, because 505030211981 - 2¹⁴ = 505030195597 is a prime.

It is a super-2 number, since 2×505030211981² (a number of 24 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 (505030211921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 252515105990 + 252515105991.

It is an arithmetic number, because the mean of its divisors is an integer number (252515105991).

Almost surely, 2^505030211981 is an apocalyptic number.

It is an amenable number.

505030211981 is a deficient number, since it is larger than the sum of its proper divisors (1).

505030211981 is an equidigital number, since it uses as much as digits as its factorization.

505030211981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10800, while the sum is 35.

The spelling of 505030211981 in words is "five hundred five billion, thirty million, two hundred eleven thousand, nine hundred eighty-one".