81124736 has 64 divisors (see below), whose sum is σ = 201519360. Its totient is φ = 31603200.

The previous prime is 81124727. The next prime is 81124787. The reversal of 81124736 is 63742118.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5741 + ... + 13971.

It is an arithmetic number, because the mean of its divisors is an integer number (3148740).

Almost surely, 2^81124736 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 81124736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100759680).

81124736 is an abundant number, since it is smaller than the sum of its proper divisors (120394624).

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

81124736 is a wasteful number, since it uses less digits than its factorization.

81124736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8263 (or 8251 counting only the distinct ones).

The product of its digits is 8064, while the sum is 32.

The square root of 81124736 is about 9006.9271119511. The cubic root of 81124736 is about 432.8968564939.

The spelling of 81124736 in words is "eighty-one million, one hundred twenty-four thousand, seven hundred thirty-six".