81806178 has 8 divisors (see below), whose sum is σ = 163612368. Its totient is φ = 27268724.

The previous prime is 81806173. The next prime is 81806183. The reversal of 81806178 is 87160818.

It is an interprime number because it is at equal distance from previous prime (81806173) and next prime (81806183).

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

81806178 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (81806173) 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, 6817176 + ... + 6817187.

It is an arithmetic number, because the mean of its divisors is an integer number (20451546).

Almost surely, 2^81806178 is an apocalyptic number.

81806178 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.

81806178 is a wasteful number, since it uses less digits than its factorization.

81806178 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13634368.

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

The square root of 81806178 is about 9044.6767769777. The cubic root of 81806178 is about 434.1055793027.

The spelling of 81806178 in words is "eighty-one million, eight hundred six thousand, one hundred seventy-eight".