991228017 has 16 divisors (see below), whose sum is σ = 1433698560. Its totient is φ = 605530752.

The previous prime is 991228009. The next prime is 991228031. The reversal of 991228017 is 710822199.

991228017 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 991228017 - 2³ = 991228009 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (991228067) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87417 + ... + 98102.

It is an arithmetic number, because the mean of its divisors is an integer number (89606160).

Almost surely, 2^991228017 is an apocalyptic number.

It is an amenable number.

991228017 is a deficient number, since it is larger than the sum of its proper divisors (442470543).

991228017 is a wasteful number, since it uses less digits than its factorization.

991228017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185672.

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 991228017 is about 31483.7738684548. The cubic root of 991228017 is about 997.0674140129.

The spelling of 991228017 in words is "nine hundred ninety-one million, two hundred twenty-eight thousand, seventeen".