991005249 has 16 divisors (see below), whose sum is σ = 1497876800. Its totient is φ = 577751616.

The previous prime is 991005247. The next prime is 991005271. The reversal of 991005249 is 942500199.

It is not a de Polignac number, because 991005249 - 2¹ = 991005247 is a prime.

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

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991005247) 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, 667954 + ... + 669435.

It is an arithmetic number, because the mean of its divisors is an integer number (93617300).

Almost surely, 2^991005249 is an apocalyptic number.

It is an amenable number.

991005249 is a deficient number, since it is larger than the sum of its proper divisors (506871551).

991005249 is a wasteful number, since it uses less digits than its factorization.

991005249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1337424.

The product of its (nonzero) digits is 29160, while the sum is 39.

The square root of 991005249 is about 31480.2358472741. The cubic root of 991005249 is about 996.9927149691.

The spelling of 991005249 in words is "nine hundred ninety-one million, five thousand, two hundred forty-nine".