81620656066260 has 72 divisors (see below), whose sum is σ = 247849161716520. Its totient is φ = 21742079275008.

The previous prime is 81620656066259. The next prime is 81620656066387. The reversal of 81620656066260 is 6266065602618.

81620656066260 is a `hidden beast` number, since 8 + 1 + 6 + 2 + 0 + 6 + 5 + 6 + 0 + 6 + 626 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 4102034521104 + 77518621545156 = 2025348^2 + 8804466^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81620656066197 and 81620656066206.

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 243884497 + ... + 244218936.

It is an arithmetic number, because the mean of its divisors is an integer number (3442349468285).

Almost surely, 2^{81620656066260} is an apocalyptic number.

It is an amenable number.

81620656066260 is an abundant number, since it is smaller than the sum of its proper divisors (166228505650260).

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

81620656066260 is a wasteful number, since it uses less digits than its factorization.

81620656066260 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488104377 (or 488104372 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 54.

The spelling of 81620656066260 in words is "eighty-one trillion, six hundred twenty billion, six hundred fifty-six million, sixty-six thousand, two hundred sixty".