81183489397 has 2 divisors, whose sum is σ = 81183489398. Its totient is φ = 81183489396.

The previous prime is 81183489349. The next prime is 81183489419. The reversal of 81183489397 is 79398438118.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80588422161 + 595067236 = 283881^2 + 24394^2 .

It is a cyclic number.

It is not a de Polignac number, because 81183489397 - 2¹⁹ = 81182965109 is a prime.

It is a super-2 number, since 2×81183489397² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81183589397) 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, 40591744698 + 40591744699.

It is an arithmetic number, because the mean of its divisors is an integer number (40591744699).

Almost surely, 2^81183489397 is an apocalyptic number.

It is an amenable number.

81183489397 is a deficient number, since it is larger than the sum of its proper divisors (1).

81183489397 is an equidigital number, since it uses as much as digits as its factorization.

81183489397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10450944, while the sum is 61.

The spelling of 81183489397 in words is "eighty-one billion, one hundred eighty-three million, four hundred eighty-nine thousand, three hundred ninety-seven".