899999921 has 2 divisors, whose sum is σ = 899999922. Its totient is φ = 899999920.

The previous prime is 899999911. The next prime is 899999929. The reversal of 899999921 is 129999998.

899999921 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., 878470321 + 21529600 = 29639^2 + 4640^2 .

It is a cyclic number.

It is not a de Polignac number, because 899999921 - 2¹⁸ = 899737777 is a prime.

It is not a weakly prime, because it can be changed into another prime (899999929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 449999960 + 449999961.

It is an arithmetic number, because the mean of its divisors is an integer number (449999961).

Almost surely, 2^899999921 is an apocalyptic number.

It is an amenable number.

899999921 is a deficient number, since it is larger than the sum of its proper divisors (1).

899999921 is an equidigital number, since it uses as much as digits as its factorization.

899999921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8503056, while the sum is 65.

The square root of 899999921 is about 29999.9986833333. The cubic root of 899999921 is about 965.4893563561.

The spelling of 899999921 in words is "eight hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred twenty-one".