81406793 has 6 divisors (see below), whose sum is σ = 88150734. Its totient is φ = 75144576.

The previous prime is 81406789. The next prime is 81406813. The reversal of 81406793 is 39760418.

It can be written as a sum of positive squares in 3 ways, for example, as 6012304 + 75394489 = 2452^2 + 8683^2 .

It is not a de Polignac number, because 81406793 - 2² = 81406789 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81406723) 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 5 ways as a sum of consecutive naturals, for example, 240680 + ... + 241017.

It is an arithmetic number, because the mean of its divisors is an integer number (14691789).

Almost surely, 2^81406793 is an apocalyptic number.

It is an amenable number.

81406793 is a deficient number, since it is larger than the sum of its proper divisors (6743941).

81406793 is a wasteful number, since it uses less digits than its factorization.

81406793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 481723 (or 481710 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 81406793 is about 9022.5713075597. The cubic root of 81406793 is about 433.3979792443.

The spelling of 81406793 in words is "eighty-one million, four hundred six thousand, seven hundred ninety-three".