99128389 has 2 divisors, whose sum is σ = 99128390. Its totient is φ = 99128388.

The previous prime is 99128353. The next prime is 99128399. The reversal of 99128389 is 98382199.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 82992100 + 16136289 = 9110^2 + 4017^2 .

It is a cyclic number.

It is not a de Polignac number, because 99128389 - 2⁹ = 99127877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99128399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49564194 + 49564195.

It is an arithmetic number, because the mean of its divisors is an integer number (49564195).

Almost surely, 2^99128389 is an apocalyptic number.

It is an amenable number.

99128389 is a deficient number, since it is larger than the sum of its proper divisors (1).

99128389 is an equidigital number, since it uses as much as digits as its factorization.

99128389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 279936, while the sum is 49.

The square root of 99128389 is about 9956.3240706598. The cubic root of 99128389 is about 462.8063929368.

The spelling of 99128389 in words is "ninety-nine million, one hundred twenty-eight thousand, three hundred eighty-nine".