81344440 has 16 divisors (see below), whose sum is σ = 183025080. Its totient is φ = 32537760.

The previous prime is 81344437. The next prime is 81344441. The reversal of 81344440 is 4444318.

It is a junction number, because it is equal to n+sod(n) for n = 81344399 and 81344408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81344441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1016766 + ... + 1016845.

Almost surely, 2^81344440 is an apocalyptic number.

It is an amenable number.

81344440 is an abundant number, since it is smaller than the sum of its proper divisors (101680640).

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

81344440 is a wasteful number, since it uses less digits than its factorization.

81344440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2033622 (or 2033618 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 28.

The square root of 81344440 is about 9019.1152559439. The cubic root of 81344440 is about 433.2872981997.

Adding to 81344440 its reverse (4444318), we get a palindrome (85788758).

The spelling of 81344440 in words is "eighty-one million, three hundred forty-four thousand, four hundred forty".