81806679 has 12 divisors (see below), whose sum is σ = 122542056. Its totient is φ = 54537624.

The previous prime is 81806677. The next prime is 81806701. The reversal of 81806679 is 97660818.

It is a happy number.

It is not a de Polignac number, because 81806679 - 2¹ = 81806677 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81806677) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 168084 + ... + 168569.

It is an arithmetic number, because the mean of its divisors is an integer number (10211838).

Almost surely, 2^81806679 is an apocalyptic number.

81806679 is a deficient number, since it is larger than the sum of its proper divisors (40735377).

81806679 is an equidigital number, since it uses as much as digits as its factorization.

81806679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336668 (or 336656 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 81806679 is about 9044.7044727841. The cubic root of 81806679 is about 434.1064654887.

The spelling of 81806679 in words is "eighty-one million, eight hundred six thousand, six hundred seventy-nine".