991002012 has 384 divisors, whose sum is σ = 3446489088. Its totient is φ = 212889600.

The previous prime is 991002011. The next prime is 991002013. The reversal of 991002012 is 210200199.

It is an interprime number because it is at equal distance from previous prime (991002011) and next prime (991002013).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991002011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4696587 + ... + 4696797.

It is an arithmetic number, because the mean of its divisors is an integer number (8975232).

Almost surely, 2^991002012 is an apocalyptic number.

991002012 is a gapful number since it is divisible by the number (92) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991002012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1723244544).

991002012 is an abundant number, since it is smaller than the sum of its proper divisors (2455487076).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991002012 is a wasteful number, since it uses less digits than its factorization.

991002012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 991002012 is about 31480.1844340213. The cubic root of 991002012 is about 996.9916294488.

The spelling of 991002012 in words is "nine hundred ninety-one million, two thousand, twelve".