78209205660 has 72 divisors (see below), whose sum is σ = 237337551360. Its totient is φ = 20846736768.

The previous prime is 78209205649. The next prime is 78209205673. The reversal of 78209205660 is 6650290287.

78209205660 is a `hidden beast` number, since 7 + 82 + 0 + 9 + 2 + 0 + 566 + 0 = 666.

It is a super-2 number, since 2×78209205660² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 326821 + ... + 513059.

It is an arithmetic number, because the mean of its divisors is an integer number (3296354880).

Almost surely, 2^78209205660 is an apocalyptic number.

It is an amenable number.

78209205660 is an abundant number, since it is smaller than the sum of its proper divisors (159128345700).

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

78209205660 is a wasteful number, since it uses less digits than its factorization.

78209205660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188587 (or 188582 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 78209205660 in words is "seventy-eight billion, two hundred nine million, two hundred five thousand, six hundred sixty".