81966340 has 24 divisors (see below), whose sum is σ = 175049280. Its totient is φ = 32230368.

The previous prime is 81966331. The next prime is 81966341. The reversal of 81966340 is 4366918.

It is a self number, because there is not a number n which added to its sum of digits gives 81966340.

It is not an unprimeable number, because it can be changed into a prime (81966341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33552 + ... + 35911.

It is an arithmetic number, because the mean of its divisors is an integer number (7293720).

Almost surely, 2^81966340 is an apocalyptic number.

It is an amenable number.

81966340 is an abundant number, since it is smaller than the sum of its proper divisors (93082940).

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

81966340 is a wasteful number, since it uses less digits than its factorization.

81966340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69531 (or 69529 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 81966340 is about 9053.5263847851. The cubic root of 81966340 is about 434.3886952189.

The spelling of 81966340 in words is "eighty-one million, nine hundred sixty-six thousand, three hundred forty".