209489775768 has 720 divisors, whose sum is σ = 767382493680. Its totient is φ = 52273009152.

The previous prime is 209489775763. The next prime is 209489775791. The reversal of 209489775768 is 867577984902.

209489775768 is a `hidden beast` number, since 2 + 0 + 9 + 48 + 9 + 7 + 7 + 576 + 8 = 666.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 209489775696 and 209489775705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209489775763) by changing a digit.

It is a polite number, since it can be written in 179 ways as a sum of consecutive naturals, for example, 276736446 + ... + 276737202.

It is an arithmetic number, because the mean of its divisors is an integer number (1065809019).

Almost surely, 2^209489775768 is an apocalyptic number.

209489775768 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209489775768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (383691246840).

209489775768 is an abundant number, since it is smaller than the sum of its proper divisors (557892717912).

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

209489775768 is a wasteful number, since it uses less digits than its factorization.

209489775768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 846 (or 801 counting only the distinct ones).

The product of its (nonzero) digits is 426746880, while the sum is 72.

The spelling of 209489775768 in words is "two hundred nine billion, four hundred eighty-nine million, seven hundred seventy-five thousand, seven hundred sixty-eight".