19991004 has 48 divisors (see below), whose sum is σ = 51166080. Its totient is φ = 6024640.

The previous prime is 19991003. The next prime is 19991009. The reversal of 19991004 is 40019991.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19991003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35227 + ... + 35789.

It is an arithmetic number, because the mean of its divisors is an integer number (1065960).

Almost surely, 2^19991004 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19991004, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25583040).

19991004 is an abundant number, since it is smaller than the sum of its proper divisors (31175076).

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

19991004 is a wasteful number, since it uses less digits than its factorization.

19991004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 850 (or 848 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 33.

The square root of 19991004 is about 4471.1300584975. The cubic root of 19991004 is about 271.4010573878.

It can be divided in two parts, 1999 and 1004, that added together give a palindrome (3003).

The spelling of 19991004 in words is "nineteen million, nine hundred ninety-one thousand, four".