81846779 has 4 divisors (see below), whose sum is σ = 93539184. Its totient is φ = 70154376.

The previous prime is 81846763. The next prime is 81846781. The reversal of 81846779 is 97764818.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97764818 = 2 ⋅48882409.

It is a cyclic number.

It is not a de Polignac number, because 81846779 - 2⁴ = 81846763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81846979) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5846192 + ... + 5846205.

It is an arithmetic number, because the mean of its divisors is an integer number (23384796).

Almost surely, 2^81846779 is an apocalyptic number.

81846779 is a deficient number, since it is larger than the sum of its proper divisors (11692405).

81846779 is a wasteful number, since it uses less digits than its factorization.

81846779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11692404.

The product of its digits is 677376, while the sum is 50.

The square root of 81846779 is about 9046.9209679316. The cubic root of 81846779 is about 434.1773840084.

The spelling of 81846779 in words is "eighty-one million, eight hundred forty-six thousand, seven hundred seventy-nine".