81428185 has 8 divisors (see below), whose sum is σ = 97868736. Its totient is φ = 65039280.

The previous prime is 81428101. The next prime is 81428189. The reversal of 81428185 is 58182418.

It is a happy number.

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

It is not a de Polignac number, because 81428185 - 2⁷ = 81428057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81428189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9351 + ... + 15820.

It is an arithmetic number, because the mean of its divisors is an integer number (12233592).

Almost surely, 2^81428185 is an apocalyptic number.

It is an amenable number.

81428185 is a deficient number, since it is larger than the sum of its proper divisors (16440551).

81428185 is a wasteful number, since it uses less digits than its factorization.

81428185 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25823.

The product of its digits is 20480, while the sum is 37.

The square root of 81428185 is about 9023.7567010641. The cubic root of 81428185 is about 433.4359385565.

The spelling of 81428185 in words is "eighty-one million, four hundred twenty-eight thousand, one hundred eighty-five".