981736781 has 2 divisors, whose sum is σ = 981736782. Its totient is φ = 981736780.

The previous prime is 981736771. The next prime is 981736787. The reversal of 981736781 is 187637189.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 921426025 + 60310756 = 30355^2 + 7766^2 .

It is an emirp because it is prime and its reverse (187637189) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-981736781 is a prime.

It is a super-2 number, since 2×981736781² = 1927614214336483922, which contains 22 as substring.

It is equal to p_49965467 and since 981736781 and 49965467 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (981736787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 490868390 + 490868391.

It is an arithmetic number, because the mean of its divisors is an integer number (490868391).

Almost surely, 2^981736781 is an apocalyptic number.

It is an amenable number.

981736781 is a deficient number, since it is larger than the sum of its proper divisors (1).

981736781 is an equidigital number, since it uses as much as digits as its factorization.

981736781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 508032, while the sum is 50.

The square root of 981736781 is about 31332.6791226030. The cubic root of 981736781 is about 993.8748190934.

The spelling of 981736781 in words is "nine hundred eighty-one million, seven hundred thirty-six thousand, seven hundred eighty-one".