81396040 has 64 divisors (see below), whose sum is σ = 206712000. Its totient is φ = 28573440.

The previous prime is 81396031. The next prime is 81396061. The reversal of 81396040 is 4069318.

It is a junction number, because it is equal to n+sod(n) for n = 81395993 and 81396011.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9571 + ... + 15949.

It is an arithmetic number, because the mean of its divisors is an integer number (3229875).

Almost surely, 2^81396040 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 81396040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103356000).

81396040 is an abundant number, since it is smaller than the sum of its proper divisors (125315960).

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

81396040 is a wasteful number, since it uses less digits than its factorization.

81396040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6430 (or 6426 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 81396040 is about 9021.9753934490. The cubic root of 81396040 is about 433.3788959324.

The spelling of 81396040 in words is "eighty-one million, three hundred ninety-six thousand, forty".