81810773 has 8 divisors (see below), whose sum is σ = 89314176. Its totient is φ = 74318400.

The previous prime is 81810761. The next prime is 81810779. The reversal of 81810773 is 37701818.

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 81810773 - 2⁶ = 81810709 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 (81810779) 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, 24653 + ... + 27773.

It is an arithmetic number, because the mean of its divisors is an integer number (11164272).

Almost surely, 2^81810773 is an apocalyptic number.

It is an amenable number.

81810773 is a deficient number, since it is larger than the sum of its proper divisors (7503403).

81810773 is a wasteful number, since it uses less digits than its factorization.

81810773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5515.

The product of its (nonzero) digits is 9408, while the sum is 35.

The square root of 81810773 is about 9044.9307902272. The cubic root of 81810773 is about 434.1137069603.

The spelling of 81810773 in words is "eighty-one million, eight hundred ten thousand, seven hundred seventy-three".