81463968 has 120 divisors (see below), whose sum is σ = 244515348. Its totient is φ = 26597376.

The previous prime is 81463961. The next prime is 81463981. The reversal of 81463968 is 86936418.

81463968 is a `hidden beast` number, since 8 + 1 + 4 + 639 + 6 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 79067664 + 2396304 = 8892^2 + 1548^2 .

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 (81463961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 137080 + ... + 137672.

Almost surely, 2^81463968 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 81463968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122257674).

81463968 is an abundant number, since it is smaller than the sum of its proper divisors (163051380).

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

81463968 is a wasteful number, since it uses less digits than its factorization.

81463968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 668 (or 651 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 81463968 is about 9025.7391941048. The cubic root of 81463968 is about 433.4994193069.

The spelling of 81463968 in words is "eighty-one million, four hundred sixty-three thousand, nine hundred sixty-eight".