81378324 has 72 divisors (see below), whose sum is σ = 221376960. Its totient is φ = 25803360.

The previous prime is 81378313. The next prime is 81378361. The reversal of 81378324 is 42387318.

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

It is a congruent number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 449514 + ... + 449694.

It is an arithmetic number, because the mean of its divisors is an integer number (3074680).

Almost surely, 2^81378324 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 81378324, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110688480).

81378324 is an abundant number, since it is smaller than the sum of its proper divisors (139998636).

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

81378324 is a wasteful number, since it uses less digits than its factorization.

81378324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398 (or 209 counting only the distinct ones).

The product of its digits is 32256, while the sum is 36.

The square root of 81378324 is about 9020.9935151290. The cubic root of 81378324 is about 433.3474517425.

It can be divided in two parts, 8137 and 8324, that added together give a palindrome (16461).

The spelling of 81378324 in words is "eighty-one million, three hundred seventy-eight thousand, three hundred twenty-four".