81300813 has 16 divisors (see below), whose sum is σ = 118705152. Its totient is φ = 49086000.

The previous prime is 81300809. The next prime is 81300839. The reversal of 81300813 is 31800318.

It is not a de Polignac number, because 81300813 - 2² = 81300809 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81300013) 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 15 ways as a sum of consecutive naturals, for example, 4398 + ... + 13488.

It is an arithmetic number, because the mean of its divisors is an integer number (7419072).

Almost surely, 2^81300813 is an apocalyptic number.

It is an amenable number.

81300813 is a deficient number, since it is larger than the sum of its proper divisors (37404339).

81300813 is a wasteful number, since it uses less digits than its factorization.

81300813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9376.

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 81300813 is about 9016.6963462235. The cubic root of 81300813 is about 433.2098235116.

It can be divided in two parts, 81300 and 813, that multiplied together give a square (66096900 = 8130²).

The spelling of 81300813 in words is "eighty-one million, three hundred thousand, eight hundred thirteen".