208868661604656 has 480 divisors, whose sum is σ = 630991297305600. Its totient is φ = 66114422277120.

The previous prime is 208868661604651. The next prime is 208868661604657. The reversal of 208868661604656 is 656406166868802.

208868661604656 is a `hidden beast` number, since 2 + 0 + 8 + 8 + 6 + 8 + 6 + 6 + 1 + 604 + 6 + 5 + 6 = 666.

It is a super-2 number, since 2×208868661604656² (a number of 29 digits) contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (208868661604651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 45495240921 + ... + 45495245511.

It is an arithmetic number, because the mean of its divisors is an integer number (1314565202720).

Almost surely, 2^{208868661604656} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 208868661604656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (315495648652800).

208868661604656 is an abundant number, since it is smaller than the sum of its proper divisors (422122635700944).

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

208868661604656 is a wasteful number, since it uses less digits than its factorization.

208868661604656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6514 (or 6465 counting only the distinct ones).

The product of its (nonzero) digits is 955514880, while the sum is 72.

The spelling of 208868661604656 in words is "two hundred eight trillion, eight hundred sixty-eight billion, six hundred sixty-one million, six hundred four thousand, six hundred fifty-six".