81748512 has 144 divisors (see below), whose sum is σ = 251203680. Its totient is φ = 25122816.

The previous prime is 81748501. The next prime is 81748523. The reversal of 81748512 is 21584718.

It is an interprime number because it is at equal distance from previous prime (81748501) and next prime (81748523).

It is a tau number, because it is divible by the number of its divisors (144).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 288723 + ... + 289005.

It is an arithmetic number, because the mean of its divisors is an integer number (1744470).

Almost surely, 2^81748512 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 81748512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125601840).

81748512 is an abundant number, since it is smaller than the sum of its proper divisors (169455168).

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

81748512 is a wasteful number, since it uses less digits than its factorization.

81748512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 375 (or 364 counting only the distinct ones).

The product of its digits is 17920, while the sum is 36.

The square root of 81748512 is about 9041.4883730501. The cubic root of 81748512 is about 434.0035535255.

The spelling of 81748512 in words is "eighty-one million, seven hundred forty-eight thousand, five hundred twelve".