81866403 has 8 divisors (see below), whose sum is σ = 121283600. Its totient is φ = 54577584.

The previous prime is 81866401. The next prime is 81866419. The reversal of 81866403 is 30466818.

It is a happy number.

81866403 is a `hidden beast` number, since 8 + 1 + 8 + 6 + 640 + 3 = 666.

It is not a de Polignac number, because 81866403 - 2¹ = 81866401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81866401) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1516018 + ... + 1516071.

It is an arithmetic number, because the mean of its divisors is an integer number (15160450).

Almost surely, 2^81866403 is an apocalyptic number.

81866403 is a deficient number, since it is larger than the sum of its proper divisors (39417197).

81866403 is a wasteful number, since it uses less digits than its factorization.

81866403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3032098 (or 3032092 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 81866403 is about 9048.0054708206. The cubic root of 81866403 is about 434.2120814281.

The spelling of 81866403 in words is "eighty-one million, eight hundred sixty-six thousand, four hundred three".