81617443 has 2 divisors, whose sum is σ = 81617444. Its totient is φ = 81617442.

The previous prime is 81617441. The next prime is 81617447. The reversal of 81617443 is 34471618.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81617443 - 2¹ = 81617441 is a prime.

It is a super-2 number, since 2×81617443² = 13322814003716498, which contains 22 as substring.

Together with 81617441, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 81617399 and 81617408.

It is not a weakly prime, because it can be changed into another prime (81617441) 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 as a sum of consecutive naturals, namely, 40808721 + 40808722.

It is an arithmetic number, because the mean of its divisors is an integer number (40808722).

Almost surely, 2^81617443 is an apocalyptic number.

81617443 is a deficient number, since it is larger than the sum of its proper divisors (1).

81617443 is an equidigital number, since it uses as much as digits as its factorization.

81617443 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 34.

The square root of 81617443 is about 9034.2372671964. The cubic root of 81617443 is about 433.7714806361.

The spelling of 81617443 in words is "eighty-one million, six hundred seventeen thousand, four hundred forty-three".