999637993 has 2 divisors, whose sum is σ = 999637994. Its totient is φ = 999637992.

The previous prime is 999637987. The next prime is 999638009. The reversal of 999637993 is 399736999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 942060249 + 57577744 = 30693^2 + 7588^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999637993 is a prime.

It is a super-2 number, since 2×999637993² = 1998552234098136098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (999637913) 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, 499818996 + 499818997.

It is an arithmetic number, because the mean of its divisors is an integer number (499818997).

Almost surely, 2^999637993 is an apocalyptic number.

It is an amenable number.

999637993 is a deficient number, since it is larger than the sum of its proper divisors (1).

999637993 is an equidigital number, since it uses as much as digits as its factorization.

999637993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22320522, while the sum is 64.

The square root of 999637993 is about 31617.0522503285. The cubic root of 999637993 is about 999.8793164361.

The spelling of 999637993 in words is "nine hundred ninety-nine million, six hundred thirty-seven thousand, nine hundred ninety-three".