81191862024 has 512 divisors, whose sum is σ = 272509440000. Its totient is φ = 19971753984.

The previous prime is 81191862019. The next prime is 81191862061. The reversal of 81191862024 is 42026819118.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 148430919 + ... + 148431465.

It is an arithmetic number, because the mean of its divisors is an integer number (532245000).

Almost surely, 2^81191862024 is an apocalyptic number.

81191862024 is a gapful number since it is divisible by the number (84) 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 81191862024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136254720000).

81191862024 is an abundant number, since it is smaller than the sum of its proper divisors (191317577976).

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

81191862024 is a wasteful number, since it uses less digits than its factorization.

81191862024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 682 (or 664 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The spelling of 81191862024 in words is "eighty-one billion, one hundred ninety-one million, eight hundred sixty-two thousand, twenty-four".