81974592 has 196 divisors, whose sum is σ = 279842976. Its totient is φ = 23328000.

The previous prime is 81974579. The next prime is 81974593. The reversal of 81974592 is 29547918.

81974592 is a `hidden beast` number, since 8 + 197 + 459 + 2 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

Its product of digits (181440) is a multiple of the sum of its prime factors (288).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81974593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 326467 + ... + 326717.

Almost surely, 2^81974592 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 81974592, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (139921488).

81974592 is an abundant number, since it is smaller than the sum of its proper divisors (197868384).

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

81974592 is an equidigital number, since it uses as much as digits as its factorization.

81974592 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288 (or 263 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 81974592 is about 9053.9821073382. The cubic root of 81974592 is about 434.4032721587.

The spelling of 81974592 in words is "eighty-one million, nine hundred seventy-four thousand, five hundred ninety-two".