513223981 has 2 divisors, whose sum is σ = 513223982. Its totient is φ = 513223980.

The previous prime is 513223979. The next prime is 513224009. The reversal of 513223981 is 189322315.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 451350025 + 61873956 = 21245^2 + 7866^2 .

It is a cyclic number.

It is not a de Polignac number, because 513223981 - 2¹ = 513223979 is a prime.

It is a super-2 number, since 2×513223981² = 526797709346976722, which contains 22 as substring.

Together with 513223979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (513223961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 256611990 + 256611991.

It is an arithmetic number, because the mean of its divisors is an integer number (256611991).

Almost surely, 2^513223981 is an apocalyptic number.

It is an amenable number.

513223981 is a deficient number, since it is larger than the sum of its proper divisors (1).

513223981 is an equidigital number, since it uses as much as digits as its factorization.

513223981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 34.

The square root of 513223981 is about 22654.4472675896. The cubic root of 513223981 is about 800.6369827857.

The spelling of 513223981 in words is "five hundred thirteen million, two hundred twenty-three thousand, nine hundred eighty-one".