81816078 has 8 divisors (see below), whose sum is σ = 163632168. Its totient is φ = 27272024.

The previous prime is 81816061. The next prime is 81816079. The reversal of 81816078 is 87061818.

It is a sphenic number, since it is the product of 3 distinct primes.

81816078 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81816079) 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 3 ways as a sum of consecutive naturals, for example, 6818001 + ... + 6818012.

It is an arithmetic number, because the mean of its divisors is an integer number (20454021).

Almost surely, 2^81816078 is an apocalyptic number.

81816078 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81816078 is a wasteful number, since it uses less digits than its factorization.

81816078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13636018.

The product of its (nonzero) digits is 21504, while the sum is 39.

The square root of 81816078 is about 9045.2240436597. The cubic root of 81816078 is about 434.1230900906.

The spelling of 81816078 in words is "eighty-one million, eight hundred sixteen thousand, seventy-eight".