81226709 has 4 divisors (see below), whose sum is σ = 84027660. Its totient is φ = 78425760.

The previous prime is 81226693. The next prime is 81226741. The reversal of 81226709 is 90762218.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27615025 + 53611684 = 5255^2 + 7322^2 .

It is a cyclic number.

It is not a de Polignac number, because 81226709 - 2⁴ = 81226693 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 (81226759) 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 in 3 ways as a sum of consecutive naturals, for example, 1400432 + ... + 1400489.

It is an arithmetic number, because the mean of its divisors is an integer number (21006915).

Almost surely, 2^81226709 is an apocalyptic number.

It is an amenable number.

81226709 is a deficient number, since it is larger than the sum of its proper divisors (2800951).

81226709 is a wasteful number, since it uses less digits than its factorization.

81226709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2800950.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 81226709 is about 9012.5861438324. The cubic root of 81226709 is about 433.0781629204.

The spelling of 81226709 in words is "eighty-one million, two hundred twenty-six thousand, seven hundred nine".