81201449870208 has 512 divisors, whose sum is σ = 245302877952000. Its totient is φ = 26435875479552.

The previous prime is 81201449870197. The next prime is 81201449870209. The reversal of 81201449870208 is 80207894410218.

81201449870208 is a `hidden beast` number, since 8 + 120 + 1 + 4 + 498 + 7 + 0 + 20 + 8 = 666.

It is a super-2 number, since 2×81201449870208² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81201449870209) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 51295924585 + ... + 51295926167.

It is an arithmetic number, because the mean of its divisors is an integer number (479107183500).

Almost surely, 2^{81201449870208} 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 81201449870208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122651438976000).

81201449870208 is an abundant number, since it is smaller than the sum of its proper divisors (164101428081792).

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

81201449870208 is a wasteful number, since it uses less digits than its factorization.

81201449870208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3139 (or 3121 counting only the distinct ones).

The product of its (nonzero) digits is 2064384, while the sum is 54.

The spelling of 81201449870208 in words is "eighty-one trillion, two hundred one billion, four hundred forty-nine million, eight hundred seventy thousand, two hundred eight".