19509804 has 72 divisors (see below), whose sum is σ = 51510368. Its totient is φ = 6220800.

The previous prime is 19509803. The next prime is 19509811. The reversal of 19509804 is 40890591.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (19509803) 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 23 ways as a sum of consecutive naturals, for example, 129129 + ... + 129279.

Almost surely, 2^19509804 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 19509804, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25755184).

19509804 is an abundant number, since it is smaller than the sum of its proper divisors (32000564).

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

19509804 is a wasteful number, since it uses less digits than its factorization.

19509804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295 (or 290 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 19509804 is about 4416.9903780742. The cubic root of 19509804 is about 269.2057316078.

The spelling of 19509804 in words is "nineteen million, five hundred nine thousand, eight hundred four".