81708648 has 64 divisors (see below), whose sum is σ = 235200000. Its totient is φ = 23170752.

The previous prime is 81708637. The next prime is 81708661. The reversal of 81708648 is 84680718.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21603 + ... + 25101.

It is an arithmetic number, because the mean of its divisors is an integer number (3675000).

Almost surely, 2^81708648 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 81708648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117600000).

81708648 is an abundant number, since it is smaller than the sum of its proper divisors (153491352).

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

81708648 is a wasteful number, since it uses less digits than its factorization.

81708648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3654 (or 3650 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 42.

The square root of 81708648 is about 9039.2835999320. The cubic root of 81708648 is about 433.9329959490.

The spelling of 81708648 in words is "eighty-one million, seven hundred eight thousand, six hundred forty-eight".