512389981 has 4 divisors (see below), whose sum is σ = 512439772. Its totient is φ = 512340192.

The previous prime is 512389963. The next prime is 512390003. The reversal of 512389981 is 189983215.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 189983215 = 5 ⋅37996643.

It can be written as a sum of positive squares in 2 ways, for example, as 115025625 + 397364356 = 10725^2 + 19934^2 .

It is a cyclic number.

It is not a de Polignac number, because 512389981 - 2¹⁵ = 512357213 is a prime.

It is a super-2 number, since 2×512389981² = 525086985258360722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (512389931) 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 in 3 ways as a sum of consecutive naturals, for example, 3096 + ... + 32161.

It is an arithmetic number, because the mean of its divisors is an integer number (128109943).

Almost surely, 2^512389981 is an apocalyptic number.

It is an amenable number.

512389981 is a deficient number, since it is larger than the sum of its proper divisors (49791).

512389981 is a wasteful number, since it uses less digits than its factorization.

512389981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49790.

The product of its digits is 155520, while the sum is 46.

The square root of 512389981 is about 22636.0328017080. The cubic root of 512389981 is about 800.2030635563.

The spelling of 512389981 in words is "five hundred twelve million, three hundred eighty-nine thousand, nine hundred eighty-one".