81441648 has 30 divisors (see below), whose sum is σ = 227923904. Its totient is φ = 27147168.

The previous prime is 81441637. The next prime is 81441667. The reversal of 81441648 is 84614418.

81441648 is a `hidden beast` number, since 8 + 1 + 4 + 4 + 1 + 648 = 666.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 282640 + ... + 282927.

Almost surely, 2^81441648 is an apocalyptic number.

It is an amenable number.

81441648 is an abundant number, since it is smaller than the sum of its proper divisors (146482256).

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

81441648 is a wasteful number, since it uses less digits than its factorization.

81441648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 565581 (or 565572 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 81441648 is about 9024.5026455755. The cubic root of 81441648 is about 433.4598247431.

The spelling of 81441648 in words is "eighty-one million, four hundred forty-one thousand, six hundred forty-eight".