81805023 has 24 divisors (see below), whose sum is σ = 121305600. Its totient is φ = 53102400.

The previous prime is 81805021. The next prime is 81805033. The reversal of 81805023 is 32050818.

It is a happy number.

81805023 is a `hidden beast` number, since 81 + 80 + 502 + 3 = 666.

It is not a de Polignac number, because 81805023 - 2¹ = 81805021 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81805021) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 70498 + ... + 71648.

It is an arithmetic number, because the mean of its divisors is an integer number (5054400).

Almost surely, 2^81805023 is an apocalyptic number.

81805023 is a deficient number, since it is larger than the sum of its proper divisors (39500577).

81805023 is a wasteful number, since it uses less digits than its factorization.

81805023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1359 (or 1356 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 81805023 is about 9044.6129270412. The cubic root of 81805023 is about 434.1035362855.

It can be divided in two parts, 8180 and 5023, that added together give a triangular number (13203 = T₁₆₂).

The spelling of 81805023 in words is "eighty-one million, eight hundred five thousand, twenty-three".