81757548 has 72 divisors (see below), whose sum is σ = 217028448. Its totient is φ = 25901568.

The previous prime is 81757541. The next prime is 81757549. The reversal of 81757548 is 84575718.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (81757541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 242436 + ... + 242772.

It is an arithmetic number, because the mean of its divisors is an integer number (3014284).

Almost surely, 2^81757548 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 81757548, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108514224).

81757548 is an abundant number, since it is smaller than the sum of its proper divisors (135270900).

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

81757548 is a wasteful number, since it uses less digits than its factorization.

81757548 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 663 (or 658 counting only the distinct ones).

The product of its digits is 313600, while the sum is 45.

The square root of 81757548 is about 9041.9880557320. The cubic root of 81757548 is about 434.0195436703.

The spelling of 81757548 in words is "eighty-one million, seven hundred fifty-seven thousand, five hundred forty-eight".