991219027 has 2 divisors, whose sum is σ = 991219028. Its totient is φ = 991219026.

The previous prime is 991219013. The next prime is 991219121. The reversal of 991219027 is 720912199.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991219027 is a prime.

It is not a weakly prime, because it can be changed into another prime (991219007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495609513 + 495609514.

It is an arithmetic number, because the mean of its divisors is an integer number (495609514).

Almost surely, 2^991219027 is an apocalyptic number.

991219027 is a deficient number, since it is larger than the sum of its proper divisors (1).

991219027 is an equidigital number, since it uses as much as digits as its factorization.

991219027 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 40.

The square root of 991219027 is about 31483.6310961744. The cubic root of 991219027 is about 997.0643996835.

The spelling of 991219027 in words is "nine hundred ninety-one million, two hundred nineteen thousand, twenty-seven".