990128039321 has 2 divisors, whose sum is σ = 990128039322. Its totient is φ = 990128039320.

The previous prime is 990128039309. The next prime is 990128039357. The reversal of 990128039321 is 123930821099.

990128039321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 815183265625 + 174944773696 = 902875^2 + 418264^2 .

It is a cyclic number.

It is not a de Polignac number, because 990128039321 - 2³⁴ = 972948170137 is a prime.

It is not a weakly prime, because it can be changed into another prime (990128039371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495064019660 + 495064019661.

It is an arithmetic number, because the mean of its divisors is an integer number (495064019661).

Almost surely, 2^990128039321 is an apocalyptic number.

It is an amenable number.

990128039321 is a deficient number, since it is larger than the sum of its proper divisors (1).

990128039321 is an equidigital number, since it uses as much as digits as its factorization.

990128039321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 209952, while the sum is 47.

The spelling of 990128039321 in words is "nine hundred ninety billion, one hundred twenty-eight million, thirty-nine thousand, three hundred twenty-one".