81814815 has 12 divisors (see below), whose sum is σ = 141812424. Its totient is φ = 43634544.

The previous prime is 81814801. The next prime is 81814867. The reversal of 81814815 is 51841818.

It is a happy number.

It is not a de Polignac number, because 81814815 - 2⁶ = 81814751 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81814815.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 909009 + ... + 909098.

It is an arithmetic number, because the mean of its divisors is an integer number (11817702).

Almost surely, 2^81814815 is an apocalyptic number.

81814815 is a deficient number, since it is larger than the sum of its proper divisors (59997609).

81814815 is a wasteful number, since it uses less digits than its factorization.

81814815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1818118 (or 1818115 counting only the distinct ones).

The product of its digits is 10240, while the sum is 36.

The square root of 81814815 is about 9045.1542275408. The cubic root of 81814815 is about 434.1208562172.

It can be divided in two parts, 8181 and 4815, that added together give a square (12996 = 114²).

The spelling of 81814815 in words is "eighty-one million, eight hundred fourteen thousand, eight hundred fifteen".