81278336 has 32 divisors (see below), whose sum is σ = 163550880. Its totient is φ = 40230400.

The previous prime is 81278321. The next prime is 81278339. The reversal of 81278336 is 63387218.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 81278336.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81278339) 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, 9785 + ... + 16071.

It is an arithmetic number, because the mean of its divisors is an integer number (5110965).

Almost surely, 2^81278336 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 81278336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81775440).

81278336 is an abundant number, since it is smaller than the sum of its proper divisors (82272544).

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

81278336 is a wasteful number, since it uses less digits than its factorization.

81278336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6402 (or 6390 counting only the distinct ones).

The product of its digits is 48384, while the sum is 38.

The square root of 81278336 is about 9015.4498501184. The cubic root of 81278336 is about 433.1698970774.

The spelling of 81278336 in words is "eighty-one million, two hundred seventy-eight thousand, three hundred thirty-six".