81231648 has 48 divisors (see below), whose sum is σ = 213917760. Its totient is φ = 26990336.

The previous prime is 81231641. The next prime is 81231649. The reversal of 81231648 is 84613218.

It is a tau number, because it is divible by the number of its divisors (48).

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

It is not an unprimeable number, because it can be changed into a prime (81231641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33286 + ... + 35642.

It is an arithmetic number, because the mean of its divisors is an integer number (4456620).

Almost surely, 2^81231648 is an apocalyptic number.

It is an amenable number.

81231648 is an abundant number, since it is smaller than the sum of its proper divisors (132686112).

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

81231648 is a wasteful number, since it uses less digits than its factorization.

81231648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2729 (or 2721 counting only the distinct ones).

The product of its digits is 9216, while the sum is 33.

The square root of 81231648 is about 9012.8601453701. The cubic root of 81231648 is about 433.0869405328.

The spelling of 81231648 in words is "eighty-one million, two hundred thirty-one thousand, six hundred forty-eight".