81214250813 has 2 divisors, whose sum is σ = 81214250814. Its totient is φ = 81214250812.

The previous prime is 81214250779. The next prime is 81214250849. The reversal of 81214250813 is 31805241218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75720179929 + 5494070884 = 275173^2 + 74122^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81214250813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81214250413) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40607125406 + 40607125407.

It is an arithmetic number, because the mean of its divisors is an integer number (40607125407).

Almost surely, 2^81214250813 is an apocalyptic number.

It is an amenable number.

81214250813 is a deficient number, since it is larger than the sum of its proper divisors (1).

81214250813 is an equidigital number, since it uses as much as digits as its factorization.

81214250813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15360, while the sum is 35.

The spelling of 81214250813 in words is "eighty-one billion, two hundred fourteen million, two hundred fifty thousand, eight hundred thirteen".