81875664 has 160 divisors (see below), whose sum is σ = 258316800. Its totient is φ = 24675840.

The previous prime is 81875641. The next prime is 81875669. The reversal of 81875664 is 46657818.

It is a happy number.

81875664 is a `hidden beast` number, since 8 + 1 + 87 + 566 + 4 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81875669) 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 31 ways as a sum of consecutive naturals, for example, 342457 + ... + 342695.

It is an arithmetic number, because the mean of its divisors is an integer number (1614480).

Almost surely, 2^81875664 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 81875664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129158400).

81875664 is an abundant number, since it is smaller than the sum of its proper divisors (176441136).

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

81875664 is a wasteful number, since it uses less digits than its factorization.

81875664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330 (or 318 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The square root of 81875664 is about 9048.5172265957. The cubic root of 81875664 is about 434.2284539827.

The spelling of 81875664 in words is "eighty-one million, eight hundred seventy-five thousand, six hundred sixty-four".