81313273 has 2 divisors, whose sum is σ = 81313274. Its totient is φ = 81313272.

The previous prime is 81313241. The next prime is 81313319. The reversal of 81313273 is 37231318.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50310649 + 31002624 = 7093^2 + 5568^2 .

It is a cyclic number.

It is not a de Polignac number, because 81313273 - 2⁵ = 81313241 is a prime.

It is a super-2 number, since 2×81313273² = 13223696731945058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81313213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40656636 + 40656637.

It is an arithmetic number, because the mean of its divisors is an integer number (40656637).

Almost surely, 2^81313273 is an apocalyptic number.

It is an amenable number.

81313273 is a deficient number, since it is larger than the sum of its proper divisors (1).

81313273 is an equidigital number, since it uses as much as digits as its factorization.

81313273 is an odious number, because the sum of its binary digits is odd.

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

The square root of 81313273 is about 9017.3872601769. The cubic root of 81313273 is about 433.2319533382.

The spelling of 81313273 in words is "eighty-one million, three hundred thirteen thousand, two hundred seventy-three".