81858003709 has 2 divisors, whose sum is σ = 81858003710. Its totient is φ = 81858003708.

The previous prime is 81858003671. The next prime is 81858003719. The reversal of 81858003709 is 90730085818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50544931684 + 31313072025 = 224822^2 + 176955^2 .

It is a cyclic number.

It is not a de Polignac number, because 81858003709 - 2¹⁹ = 81857479421 is a prime.

It is a super-3 number, since 3×81858003709³ (a number of 34 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81858003719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40929001854 + 40929001855.

It is an arithmetic number, because the mean of its divisors is an integer number (40929001855).

Almost surely, 2^81858003709 is an apocalyptic number.

It is an amenable number.

81858003709 is a deficient number, since it is larger than the sum of its proper divisors (1).

81858003709 is an equidigital number, since it uses as much as digits as its factorization.

81858003709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 483840, while the sum is 49.

The spelling of 81858003709 in words is "eighty-one billion, eight hundred fifty-eight million, three thousand, seven hundred nine".