999371392681 has 2 divisors, whose sum is σ = 999371392682. Its totient is φ = 999371392680.

The previous prime is 999371392673. The next prime is 999371392699. The reversal of 999371392681 is 186293173999.

999371392681 = 706884² + 706885².

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 499686403225 + 499684989456 = 706885^2 + 706884^2 .

It is a cyclic number.

It is not a de Polignac number, because 999371392681 - 2³ = 999371392673 is a prime.

It is a super-2 number, since 2×999371392681² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (999371392651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499685696340 + 499685696341.

It is an arithmetic number, because the mean of its divisors is an integer number (499685696341).

Almost surely, 2^999371392681 is an apocalyptic number.

999371392681 is the 706885-th centered square number.

It is an amenable number.

999371392681 is a deficient number, since it is larger than the sum of its proper divisors (1).

999371392681 is an equidigital number, since it uses as much as digits as its factorization.

999371392681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39680928, while the sum is 67.

The spelling of 999371392681 in words is "nine hundred ninety-nine billion, three hundred seventy-one million, three hundred ninety-two thousand, six hundred eighty-one".