81503878579200 has 1980 divisors, whose sum is σ = 382993577212752. Its totient is φ = 16935638630400.

The previous prime is 81503878579199. The next prime is 81503878579229. The reversal of 81503878579200 is 297587830518.

81503878579200 is a `hidden beast` number, since 8 + 1 + 5 + 0 + 38 + 7 + 8 + 579 + 20 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1980).

It is a super-2 number, since 2×81503878579200² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 179 ways as a sum of consecutive naturals, for example, 1117633939 + ... + 1117706861.

Almost surely, 2^{81503878579200} is an apocalyptic number.

81503878579200 is a gapful number since it is divisible by the number (80) 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 81503878579200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191496788606376).

81503878579200 is an abundant number, since it is smaller than the sum of its proper divisors (301489698633552).

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

81503878579200 is a wasteful number, since it uses less digits than its factorization.

81503878579200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72990 (or 72951 counting only the distinct ones).

The product of its (nonzero) digits is 33868800, while the sum is 63.

The spelling of 81503878579200 in words is "eighty-one trillion, five hundred three billion, eight hundred seventy-eight million, five hundred seventy-nine thousand, two hundred".