991840529 has 2 divisors, whose sum is σ = 991840530. Its totient is φ = 991840528.

The previous prime is 991840511. The next prime is 991840579. The reversal of 991840529 is 925048199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 958026304 + 33814225 = 30952^2 + 5815^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991840529 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (991840579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495920264 + 495920265.

It is an arithmetic number, because the mean of its divisors is an integer number (495920265).

Almost surely, 2^991840529 is an apocalyptic number.

It is an amenable number.

991840529 is a deficient number, since it is larger than the sum of its proper divisors (1).

991840529 is an equidigital number, since it uses as much as digits as its factorization.

991840529 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 47.

The square root of 991840529 is about 31493.4997896391. The cubic root of 991840529 is about 997.2727451762.

The spelling of 991840529 in words is "nine hundred ninety-one million, eight hundred forty thousand, five hundred twenty-nine".