81908356362523 has 2 divisors, whose sum is σ = 81908356362524. Its totient is φ = 81908356362522.

The previous prime is 81908356362491. The next prime is 81908356362563. The reversal of 81908356362523 is 32526365380918.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81908356362523 - 2⁵ = 81908356362491 is a prime.

It is not a weakly prime, because it can be changed into another prime (81908356362563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40954178181261 + 40954178181262.

It is an arithmetic number, because the mean of its divisors is an integer number (40954178181262).

Almost surely, 2^{81908356362523} is an apocalyptic number.

81908356362523 is a deficient number, since it is larger than the sum of its proper divisors (1).

81908356362523 is an equidigital number, since it uses as much as digits as its factorization.

81908356362523 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55987200, while the sum is 61.

The spelling of 81908356362523 in words is "eighty-one trillion, nine hundred eight billion, three hundred fifty-six million, three hundred sixty-two thousand, five hundred twenty-three".