81442563552 has 288 divisors, whose sum is σ = 276894858240. Its totient is φ = 22201344000.

The previous prime is 81442563533. The next prime is 81442563577. The reversal of 81442563552 is 25536524418.

81442563552 is a `hidden beast` number, since 8 + 1 + 4 + 4 + 2 + 5 + 635 + 5 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a junction number, because it is equal to n+sod(n) for n = 81442563498 and 81442563507.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 20353552 + ... + 20357552.

It is an arithmetic number, because the mean of its divisors is an integer number (961440480).

Almost surely, 2^81442563552 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 81442563552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (138447429120).

81442563552 is an abundant number, since it is smaller than the sum of its proper divisors (195452294688).

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

81442563552 is a wasteful number, since it uses less digits than its factorization.

81442563552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4486 (or 4475 counting only the distinct ones).

The product of its digits is 1152000, while the sum is 45.

The spelling of 81442563552 in words is "eighty-one billion, four hundred forty-two million, five hundred sixty-three thousand, five hundred fifty-two".