999961931 has 2 divisors, whose sum is σ = 999961932. Its totient is φ = 999961930.

The previous prime is 999961891. The next prime is 999961939. The reversal of 999961931 is 139169999.

It is a strong prime.

It is an emirp because it is prime and its reverse (139169999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999961931 - 2¹⁸ = 999699787 is a prime.

It is a super-3 number, since 3×999961931³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (999961939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499980965 + 499980966.

It is an arithmetic number, because the mean of its divisors is an integer number (499980966).

Almost surely, 2^999961931 is an apocalyptic number.

999961931 is a deficient number, since it is larger than the sum of its proper divisors (1).

999961931 is an equidigital number, since it uses as much as digits as its factorization.

999961931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1062882, while the sum is 56.

The square root of 999961931 is about 31622.1746722138. The cubic root of 999961931 is about 999.9873101723.

It can be divided in two parts, 999 and 961931, that multiplied together give a palindrome (960969069).

The spelling of 999961931 in words is "nine hundred ninety-nine million, nine hundred sixty-one thousand, nine hundred thirty-one".