81749523492 has 144 divisors (see below), whose sum is σ = 255425788800. Its totient is φ = 21467579904.

The previous prime is 81749523439. The next prime is 81749523509. The reversal of 81749523492 is 29432594718.

81749523492 is a `hidden beast` number, since 8 + 1 + 74 + 9 + 523 + 49 + 2 = 666.

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, 709759 + ... + 816857.

It is an arithmetic number, because the mean of its divisors is an integer number (1773790200).

Almost surely, 2^81749523492 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 81749523492, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127712894400).

81749523492 is an abundant number, since it is smaller than the sum of its proper divisors (173676265308).

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

81749523492 is a wasteful number, since it uses less digits than its factorization.

81749523492 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107362 (or 107357 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 54.

The spelling of 81749523492 in words is "eighty-one billion, seven hundred forty-nine million, five hundred twenty-three thousand, four hundred ninety-two".