209780566087680 has 768 divisors, whose sum is σ = 854810883763200. Its totient is φ = 47804834119680.

The previous prime is 209780566087661. The next prime is 209780566087693. The reversal of 209780566087680 is 86780665087902.

209780566087680 is a `hidden beast` number, since 2 + 0 + 9 + 7 + 8 + 0 + 5 + 6 + 608 + 7 + 6 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (768).

It is a super-2 number, since 2×209780566087680² (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 a junction number, because it is equal to n+sod(n) for n = 209780566087599 and 209780566087608.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 640440424 + ... + 640767896.

It is an arithmetic number, because the mean of its divisors is an integer number (1113035004900).

Almost surely, 2^{209780566087680} is an apocalyptic number.

209780566087680 is a gapful number since it is divisible by the number (20) 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 209780566087680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (427405441881600).

209780566087680 is an abundant number, since it is smaller than the sum of its proper divisors (645030317675520).

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

209780566087680 is a wasteful number, since it uses less digits than its factorization.

209780566087680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327847 (or 327821 counting only the distinct ones).

The product of its (nonzero) digits is 487710720, while the sum is 72.

The spelling of 209780566087680 in words is "two hundred nine trillion, seven hundred eighty billion, five hundred sixty-six million, eighty-seven thousand, six hundred eighty".