990803557 has 2 divisors, whose sum is σ = 990803558. Its totient is φ = 990803556.

The previous prime is 990803459. The next prime is 990803599. The reversal of 990803557 is 755308099.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 895565476 + 95238081 = 29926^2 + 9759^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-990803557 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (990809557) 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, 495401778 + 495401779.

It is an arithmetic number, because the mean of its divisors is an integer number (495401779).

Almost surely, 2^990803557 is an apocalyptic number.

It is an amenable number.

990803557 is a deficient number, since it is larger than the sum of its proper divisors (1).

990803557 is an equidigital number, since it uses as much as digits as its factorization.

990803557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 340200, while the sum is 46.

The square root of 990803557 is about 31477.0322139810. The cubic root of 990803557 is about 996.9250735185.

The spelling of 990803557 in words is "nine hundred ninety million, eight hundred three thousand, five hundred fifty-seven".