19911012 has 96 divisors (see below), whose sum is σ = 56609280. Its totient is φ = 5368320.

The previous prime is 19910999. The next prime is 19911041. The reversal of 19911012 is 21011991.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42403 + ... + 42869.

It is an arithmetic number, because the mean of its divisors is an integer number (589680).

Almost surely, 2^19911012 is an apocalyptic number.

19911012 is a gapful number since it is divisible by the number (12) 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 19911012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28304640).

19911012 is an abundant number, since it is smaller than the sum of its proper divisors (36698268).

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

19911012 is a wasteful number, since it uses less digits than its factorization.

19911012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521 (or 519 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 24.

The square root of 19911012 is about 4462.1757025021. The cubic root of 19911012 is about 271.0385787682.

It can be divided in two parts, 1991 and 1012, that added together give a palindrome (3003).

The spelling of 19911012 in words is "nineteen million, nine hundred eleven thousand, twelve".