991327229 has 2 divisors, whose sum is σ = 991327230. Its totient is φ = 991327228.

The previous prime is 991327219. The next prime is 991327283. The reversal of 991327229 is 922723199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 496264729 + 495062500 = 22277^2 + 22250^2 .

It is a cyclic number.

It is not a de Polignac number, because 991327229 - 2¹⁶ = 991261693 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 991327229.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991327219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495663614 + 495663615.

It is an arithmetic number, because the mean of its divisors is an integer number (495663615).

Almost surely, 2^991327229 is an apocalyptic number.

It is an amenable number.

991327229 is a deficient number, since it is larger than the sum of its proper divisors (1).

991327229 is an equidigital number, since it uses as much as digits as its factorization.

991327229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 44.

The square root of 991327229 is about 31485.3494343004. The cubic root of 991327229 is about 997.1006783915.

The spelling of 991327229 in words is "nine hundred ninety-one million, three hundred twenty-seven thousand, two hundred twenty-nine".