991528193 has 2 divisors, whose sum is σ = 991528194. Its totient is φ = 991528192.

The previous prime is 991528189. The next prime is 991528199. The reversal of 991528193 is 391825199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 989920369 + 1607824 = 31463^2 + 1268^2 .

It is an emirp because it is prime and its reverse (391825199) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 991528193 - 2² = 991528189 is a prime.

It is not a weakly prime, because it can be changed into another prime (991528199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495764096 + 495764097.

It is an arithmetic number, because the mean of its divisors is an integer number (495764097).

Almost surely, 2^991528193 is an apocalyptic number.

It is an amenable number.

991528193 is a deficient number, since it is larger than the sum of its proper divisors (1).

991528193 is an equidigital number, since it uses as much as digits as its factorization.

991528193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 174960, while the sum is 47.

The square root of 991528193 is about 31488.5406616439. The cubic root of 991528193 is about 997.1680519744.

The spelling of 991528193 in words is "nine hundred ninety-one million, five hundred twenty-eight thousand, one hundred ninety-three".