999981430681 has 2 divisors, whose sum is σ = 999981430682. Its totient is φ = 999981430680.

The previous prime is 999981430673. The next prime is 999981430733. The reversal of 999981430681 is 186034189999.

It is the 408245-th star number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 998432614656 + 1548816025 = 999216^2 + 39355^2 .

It is a cyclic number.

It is not a de Polignac number, because 999981430681 - 2³ = 999981430673 is a prime.

It is a super-2 number, since 2×999981430681² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (999981430621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499990715340 + 499990715341.

It is an arithmetic number, because the mean of its divisors is an integer number (499990715341).

Almost surely, 2^999981430681 is an apocalyptic number.

It is an amenable number.

999981430681 is a deficient number, since it is larger than the sum of its proper divisors (1).

999981430681 is an equidigital number, since it uses as much as digits as its factorization.

999981430681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30233088, while the sum is 67.

The spelling of 999981430681 in words is "nine hundred ninety-nine billion, nine hundred eighty-one million, four hundred thirty thousand, six hundred eighty-one".