209481805172 has 12 divisors (see below), whose sum is σ = 370712183940. Its totient is φ = 103564038336.

The previous prime is 209481805171. The next prime is 209481805229. The reversal of 209481805172 is 271508184902.

It can be written as a sum of positive squares in 2 ways, for example, as 42367635556 + 167114169616 = 205834^2 + 408796^2 .

It is a super-3 number, since 3×209481805172³ (a number of 35 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209481805171) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 294215663 + ... + 294216374.

It is an arithmetic number, because the mean of its divisors is an integer number (30892681995).

Almost surely, 2^209481805172 is an apocalyptic number.

It is an amenable number.

209481805172 is a deficient number, since it is larger than the sum of its proper divisors (161230378768).

209481805172 is a wasteful number, since it uses less digits than its factorization.

209481805172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588432130 (or 588432128 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 47.

The spelling of 209481805172 in words is "two hundred nine billion, four hundred eighty-one million, eight hundred five thousand, one hundred seventy-two".