81619 has 2 divisors, whose sum is σ = 81620. Its totient is φ = 81618.

The previous prime is 81611. The next prime is 81629. The reversal of 81619 is 91618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81619 - 2³ = 81611 is a prime.

It is a super-2 number, since 2×81619² = 13323322322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81593 and 81602.

It is not a weakly prime, because it can be changed into another prime (81611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40809 + 40810.

It is an arithmetic number, because the mean of its divisors is an integer number (40810).

2⁸¹⁶¹⁹ is an apocalyptic number.

81619 is a deficient number, since it is larger than the sum of its proper divisors (1).

81619 is an equidigital number, since it uses as much as digits as its factorization.

81619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432, while the sum is 25.

The square root of 81619 is about 285.6903918580. The cubic root of 81619 is about 43.3774238943.

Subtracting 81619 from its reverse (91618), we obtain a palindrome (9999).

The spelling of 81619 in words is "eighty-one thousand, six hundred nineteen".