209789648784 has 105 divisors (see below), whose sum is σ = 609566114209. Its totient is φ = 69913393920.

The previous prime is 209789648777. The next prime is 209789648813. The reversal of 209789648784 is 487846987902.

The square root of 209789648784 is 458028.

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

It can be written as a sum of positive squares in only one way, i.e., 206635703184 + 3153945600 = 454572^2 + 56160^2 .

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 49464904 + ... + 49469144.

Almost surely, 2^209789648784 is an apocalyptic number.

209789648784 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

209789648784 is the 458028-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209789648784

209789648784 is an abundant number, since it is smaller than the sum of its proper divisors (399776465425).

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

209789648784 is an frugal number, since it uses more digits than its factorization.

209789648784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8508 (or 4246 counting only the distinct ones).

The product of its (nonzero) digits is 390168576, while the sum is 72.

The spelling of 209789648784 in words is "two hundred nine billion, seven hundred eighty-nine million, six hundred forty-eight thousand, seven hundred eighty-four".