81817373 has 8 divisors (see below), whose sum is σ = 90140256. Its totient is φ = 73642000.

The previous prime is 81817369. The next prime is 81817391. The reversal of 81817373 is 37371818.

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 81817373 - 2² = 81817369 is a prime.

It is a super-2 number, since 2×81817373² = 13388165049242258, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81817303) 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, 35711 + ... + 37932.

It is an arithmetic number, because the mean of its divisors is an integer number (11267532).

Almost surely, 2^81817373 is an apocalyptic number.

It is an amenable number.

81817373 is a deficient number, since it is larger than the sum of its proper divisors (8322883).

81817373 is a wasteful number, since it uses less digits than its factorization.

81817373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73755.

The product of its digits is 28224, while the sum is 38.

The square root of 81817373 is about 9045.2956281152. The cubic root of 81817373 is about 434.1253805387.

The spelling of 81817373 in words is "eighty-one million, eight hundred seventeen thousand, three hundred seventy-three".