999888521 has 2 divisors, whose sum is σ = 999888522. Its totient is φ = 999888520.

The previous prime is 999888497. The next prime is 999888529. The reversal of 999888521 is 125888999.

999888521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 598487296 + 401401225 = 24464^2 + 20035^2 .

It is an emirp because it is prime and its reverse (125888999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999888521 - 2⁶ = 999888457 is a prime.

It is a Chen prime.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (999888529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499944260 + 499944261.

It is an arithmetic number, because the mean of its divisors is an integer number (499944261).

Almost surely, 2^999888521 is an apocalyptic number.

It is an amenable number.

999888521 is a deficient number, since it is larger than the sum of its proper divisors (1).

999888521 is an equidigital number, since it uses as much as digits as its factorization.

999888521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3732480, while the sum is 59.

The square root of 999888521 is about 31621.0139148004. The cubic root of 999888521 is about 999.9628389524.

The spelling of 999888521 in words is "nine hundred ninety-nine million, eight hundred eighty-eight thousand, five hundred twenty-one".