81814825 has 12 divisors (see below), whose sum is σ = 102351708. Its totient is φ = 64870400.

The previous prime is 81814801. The next prime is 81814867. The reversal of 81814825 is 52841818.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 3013696 + 78801129 = 1736^2 + 8877^2 .

It is not a de Polignac number, because 81814825 - 2⁵ = 81814793 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 11656 + ... + 17305.

It is an arithmetic number, because the mean of its divisors is an integer number (8529309).

Almost surely, 2^81814825 is an apocalyptic number.

It is an amenable number.

81814825 is a deficient number, since it is larger than the sum of its proper divisors (20536883).

81814825 is a wasteful number, since it uses less digits than its factorization.

81814825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29084 (or 29079 counting only the distinct ones).

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

The square root of 81814825 is about 9045.1547803230. The cubic root of 81814825 is about 434.1208739043.

The spelling of 81814825 in words is "eighty-one million, eight hundred fourteen thousand, eight hundred twenty-five".