990689243 has 2 divisors, whose sum is σ = 990689244. Its totient is φ = 990689242.

The previous prime is 990689239. The next prime is 990689291. The reversal of 990689243 is 342986099.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 990689243 - 2² = 990689239 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 990689191 and 990689200.

It is not a weakly prime, because it can be changed into another prime (990689233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495344621 + 495344622.

It is an arithmetic number, because the mean of its divisors is an integer number (495344622).

Almost surely, 2^990689243 is an apocalyptic number.

990689243 is a deficient number, since it is larger than the sum of its proper divisors (1).

990689243 is an equidigital number, since it uses as much as digits as its factorization.

990689243 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 839808, while the sum is 50.

The square root of 990689243 is about 31475.2163296775. The cubic root of 990689243 is about 996.8867319538.

The spelling of 990689243 in words is "nine hundred ninety million, six hundred eighty-nine thousand, two hundred forty-three".