509677981 has 2 divisors, whose sum is σ = 509677982. Its totient is φ = 509677980.

The previous prime is 509677979. The next prime is 509678009. The reversal of 509677981 is 189776905.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 494350756 + 15327225 = 22234^2 + 3915^2 .

It is a cyclic number.

It is not a de Polignac number, because 509677981 - 2¹ = 509677979 is a prime.

It is a super-2 number, since 2×509677981² = 519543288632472722, which contains 22 as substring.

Together with 509677979, 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 (509677921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 254838990 + 254838991.

It is an arithmetic number, because the mean of its divisors is an integer number (254838991).

Almost surely, 2^509677981 is an apocalyptic number.

It is an amenable number.

509677981 is a deficient number, since it is larger than the sum of its proper divisors (1).

509677981 is an equidigital number, since it uses as much as digits as its factorization.

509677981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 952560, while the sum is 52.

The square root of 509677981 is about 22576.0488349932. The cubic root of 509677981 is about 798.7887822190.

The spelling of 509677981 in words is "five hundred nine million, six hundred seventy-seven thousand, nine hundred eighty-one".