81085580052 has 72 divisors (see below), whose sum is σ = 203897907360. Its totient is φ = 25010354880.

The previous prime is 81085580047. The next prime is 81085580057. The reversal of 81085580052 is 25008558018.

It is an interprime number because it is at equal distance from previous prime (81085580047) and next prime (81085580057).

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 81085579986 and 81085580013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81085580057) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 325402 + ... + 517742.

It is an arithmetic number, because the mean of its divisors is an integer number (2831915380).

Almost surely, 2^81085580052 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 81085580052, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101948953680).

81085580052 is an abundant number, since it is smaller than the sum of its proper divisors (122812327308).

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

81085580052 is a wasteful number, since it uses less digits than its factorization.

81085580052 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192453 (or 192408 counting only the distinct ones).

The product of its (nonzero) digits is 128000, while the sum is 42.

The spelling of 81085580052 in words is "eighty-one billion, eighty-five million, five hundred eighty thousand, fifty-two".