987730781 has 2 divisors, whose sum is σ = 987730782. Its totient is φ = 987730780.

The previous prime is 987730747. The next prime is 987730801. The reversal of 987730781 is 187037789.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 849197881 + 138532900 = 29141^2 + 11770^2 .

It is an emirp because it is prime and its reverse (187037789) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-987730781 is a prime.

It is a super-2 number, since 2×987730781² = 1951224191469739922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen 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 (987730721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 493865390 + 493865391.

It is an arithmetic number, because the mean of its divisors is an integer number (493865391).

Almost surely, 2^987730781 is an apocalyptic number.

It is an amenable number.

987730781 is a deficient number, since it is larger than the sum of its proper divisors (1).

987730781 is an equidigital number, since it uses as much as digits as its factorization.

987730781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 592704, while the sum is 50.

The square root of 987730781 is about 31428.1845005403. The cubic root of 987730781 is about 995.8934194137.

The spelling of 987730781 in words is "nine hundred eighty-seven million, seven hundred thirty thousand, seven hundred eighty-one".