81378044 has 24 divisors (see below), whose sum is σ = 156592128. Its totient is φ = 36696240.

The previous prime is 81378043. The next prime is 81378047. The reversal of 81378044 is 44087318.

It is a happy number.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 81377995 and 81378013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81378043) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1694 + ... + 12869.

It is an arithmetic number, because the mean of its divisors is an integer number (6524672).

Almost surely, 2^81378044 is an apocalyptic number.

It is an amenable number.

81378044 is a deficient number, since it is larger than the sum of its proper divisors (75214084).

81378044 is a wasteful number, since it uses less digits than its factorization.

81378044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14705 (or 14703 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 35.

The square root of 81378044 is about 9020.9779957608. The cubic root of 81378044 is about 433.3469547329.

The spelling of 81378044 in words is "eighty-one million, three hundred seventy-eight thousand, forty-four".