81273313 has 4 divisors (see below), whose sum is σ = 88661808. Its totient is φ = 73884820.

The previous prime is 81273307. The next prime is 81273331. The reversal of 81273313 is 31337218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81273313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81273113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3694231 + ... + 3694252.

It is an arithmetic number, because the mean of its divisors is an integer number (22165452).

Almost surely, 2^81273313 is an apocalyptic number.

It is an amenable number.

81273313 is a deficient number, since it is larger than the sum of its proper divisors (7388495).

81273313 is a wasteful number, since it uses less digits than its factorization.

81273313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7388494.

The product of its digits is 3024, while the sum is 28.

The square root of 81273313 is about 9015.1712684785. The cubic root of 81273313 is about 433.1609735958.

The spelling of 81273313 in words is "eighty-one million, two hundred seventy-three thousand, three hundred thirteen".