81349273 has 8 divisors (see below), whose sum is σ = 83921480. Its totient is φ = 78796800.

The previous prime is 81349253. The next prime is 81349291. The reversal of 81349273 is 37294318.

It can be written as a sum of positive squares in 4 ways, for example, as 59474944 + 21874329 = 7712^2 + 4677^2 .

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 81349273 - 2²⁵ = 47794841 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81349253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3673 + ... + 13273.

It is an arithmetic number, because the mean of its divisors is an integer number (10490185).

Almost surely, 2^81349273 is an apocalyptic number.

It is an amenable number.

81349273 is a deficient number, since it is larger than the sum of its proper divisors (2572207).

81349273 is a wasteful number, since it uses less digits than its factorization.

81349273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9867.

The product of its digits is 36288, while the sum is 37.

The square root of 81349273 is about 9019.3831829011. The cubic root of 81349273 is about 433.2958791428.

It can be divided in two parts, 813 and 49273, that added together give a triangular number (50086 = T₃₁₆).

The spelling of 81349273 in words is "eighty-one million, three hundred forty-nine thousand, two hundred seventy-three".