990128039291 has 2 divisors, whose sum is σ = 990128039292. Its totient is φ = 990128039290.

The previous prime is 990128039281. The next prime is 990128039309. The reversal of 990128039291 is 192930821099.

It is a weak prime.

It is an emirp because it is prime and its reverse (192930821099) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 990128039291 - 2¹⁰ = 990128038267 is a prime.

It is not a weakly prime, because it can be changed into another prime (990128039281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495064019645 + 495064019646.

It is an arithmetic number, because the mean of its divisors is an integer number (495064019646).

Almost surely, 2^990128039291 is an apocalyptic number.

990128039291 is a deficient number, since it is larger than the sum of its proper divisors (1).

990128039291 is an equidigital number, since it uses as much as digits as its factorization.

990128039291 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 629856, while the sum is 53.

The spelling of 990128039291 in words is "nine hundred ninety billion, one hundred twenty-eight million, thirty-nine thousand, two hundred ninety-one".