81774432 has 72 divisors (see below), whose sum is σ = 240589440. Its totient is φ = 26315520.

The previous prime is 81774431. The next prime is 81774449. The reversal of 81774432 is 23447718.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81774431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3457 + ... + 13247.

It is an arithmetic number, because the mean of its divisors is an integer number (3341520).

Almost surely, 2^81774432 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 81774432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120294720).

81774432 is an abundant number, since it is smaller than the sum of its proper divisors (158815008).

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

81774432 is a wasteful number, since it uses less digits than its factorization.

81774432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9836 (or 9825 counting only the distinct ones).

The product of its digits is 37632, while the sum is 36.

The square root of 81774432 is about 9042.9216517672. The cubic root of 81774432 is about 434.0494185127.

The spelling of 81774432 in words is "eighty-one million, seven hundred seventy-four thousand, four hundred thirty-two".