81378824 has 16 divisors (see below), whose sum is σ = 160616400. Its totient is φ = 38547792.

The previous prime is 81378823. The next prime is 81378827. The reversal of 81378824 is 42887318.

It is not an unprimeable number, because it can be changed into a prime (81378823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 267542 + ... + 267845.

It is an arithmetic number, because the mean of its divisors is an integer number (10038525).

Almost surely, 2^81378824 is an apocalyptic number.

It is an amenable number.

81378824 is a deficient number, since it is larger than the sum of its proper divisors (79237576).

81378824 is a wasteful number, since it uses less digits than its factorization.

81378824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 535412 (or 535408 counting only the distinct ones).

The product of its digits is 86016, while the sum is 41.

The square root of 81378824 is about 9021.0212282202. The cubic root of 81378824 is about 433.3483392568.

It can be divided in two parts, 8137 and 8824, that added together give a palindrome (16961).

The spelling of 81378824 in words is "eighty-one million, three hundred seventy-eight thousand, eight hundred twenty-four".