81679967 has 4 divisors (see below), whose sum is σ = 81983880. Its totient is φ = 81376056.

The previous prime is 81679933. The next prime is 81679973. The reversal of 81679967 is 76997618.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81679967 - 2⁸ = 81679711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81679907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151553 + ... + 152090.

It is an arithmetic number, because the mean of its divisors is an integer number (20495970).

Almost surely, 2^81679967 is an apocalyptic number.

81679967 is a deficient number, since it is larger than the sum of its proper divisors (303913).

81679967 is a wasteful number, since it uses less digits than its factorization.

81679967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303912.

The product of its digits is 1143072, while the sum is 53.

The square root of 81679967 is about 9037.6969964698. The cubic root of 81679967 is about 433.8822176081.

The spelling of 81679967 in words is "eighty-one million, six hundred seventy-nine thousand, nine hundred sixty-seven".