999960781 has 2 divisors, whose sum is σ = 999960782. Its totient is φ = 999960780.

The previous prime is 999960737. The next prime is 999960839. The reversal of 999960781 is 187069999.

It is an a-pointer prime, because the next prime (999960839) can be obtained adding 999960781 to its sum of digits (58).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 938196900 + 61763881 = 30630^2 + 7859^2 .

It is an emirp because it is prime and its reverse (187069999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999960781 - 2¹⁷ = 999829709 is a prime.

It is a super-2 number, since 2×999960781² = 1999843127076259922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999960721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499980390 + 499980391.

It is an arithmetic number, because the mean of its divisors is an integer number (499980391).

Almost surely, 2^999960781 is an apocalyptic number.

It is an amenable number.

999960781 is a deficient number, since it is larger than the sum of its proper divisors (1).

999960781 is an equidigital number, since it uses as much as digits as its factorization.

999960781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2204496, while the sum is 58.

The square root of 999960781 is about 31622.1564887659. The cubic root of 999960781 is about 999.9869268291.

The spelling of 999960781 in words is "nine hundred ninety-nine million, nine hundred sixty thousand, seven hundred eighty-one".