209205612100 has 81 divisors (see below), whose sum is σ = 463240159543. Its totient is φ = 82008197440.

The previous prime is 209205612097. The next prime is 209205612103. The reversal of 209205612100 is 1216502902.

The square root of 209205612100 is 457390.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (209205612097) and next prime (209205612103).

It can be written as a sum of positive squares in 4 ways, for example, as 1575931204 + 207629680896 = 39698^2 + 455664^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209205612103) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 242416269 + ... + 242417131.

Almost surely, 2^209205612100 is an apocalyptic number.

209205612100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

209205612100 is the 457390-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209205612100

209205612100 is an abundant number, since it is smaller than the sum of its proper divisors (254034547443).

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

209205612100 is an frugal number, since it uses more digits than its factorization.

209205612100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1846 (or 923 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The spelling of 209205612100 in words is "two hundred nine billion, two hundred five million, six hundred twelve thousand, one hundred".