81823771 has 8 divisors (see below), whose sum is σ = 86971104. Its totient is φ = 76713600.

The previous prime is 81823759. The next prime is 81823799. The reversal of 81823771 is 17732818.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81823771 - 2²⁵ = 48269339 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81823771.

It is not an unprimeable number, because it can be changed into a prime (81823171) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4680 + ... + 13621.

It is an arithmetic number, because the mean of its divisors is an integer number (10871388).

Almost surely, 2^81823771 is an apocalyptic number.

81823771 is a deficient number, since it is larger than the sum of its proper divisors (5147333).

81823771 is a wasteful number, since it uses less digits than its factorization.

81823771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18581.

The product of its digits is 18816, while the sum is 37.

The square root of 81823771 is about 9045.6492857064. The cubic root of 81823771 is about 434.1366962356.

The spelling of 81823771 in words is "eighty-one million, eight hundred twenty-three thousand, seven hundred seventy-one".