81192827520 has 384 divisors, whose sum is σ = 334509652800. Its totient is φ = 18558167040.

The previous prime is 81192827519. The next prime is 81192827533. The reversal of 81192827520 is 2572829118.

81192827520 is a `hidden beast` number, since 8 + 11 + 92 + 8 + 27 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 798775 + ... + 894665.

Almost surely, 2^81192827520 is an apocalyptic number.

81192827520 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 81192827520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (167254826400).

81192827520 is an abundant number, since it is smaller than the sum of its proper divisors (253316825280).

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

81192827520 is a wasteful number, since it uses less digits than its factorization.

81192827520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95933 (or 95908 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

The spelling of 81192827520 in words is "eighty-one billion, one hundred ninety-two million, eight hundred twenty-seven thousand, five hundred twenty".