209181838404 has 144 divisors (see below), whose sum is σ = 613801954304. Its totient is φ = 54274207680.

The previous prime is 209181838403. The next prime is 209181838499. The reversal of 209181838404 is 404838181902.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (209181838403) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 9817947 + ... + 9839229.

Almost surely, 2^209181838404 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 209181838404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (306900977152).

209181838404 is an abundant number, since it is smaller than the sum of its proper divisors (404620115900).

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

209181838404 is a wasteful number, since it uses less digits than its factorization.

209181838404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22286 (or 22273 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 48.

The spelling of 209181838404 in words is "two hundred nine billion, one hundred eighty-one million, eight hundred thirty-eight thousand, four hundred four".