81917603 has 2 divisors, whose sum is σ = 81917604. Its totient is φ = 81917602.

The previous prime is 81917581. The next prime is 81917639. The reversal of 81917603 is 30671918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81917603 - 2⁸ = 81917347 is a prime.

It is not a weakly prime, because it can be changed into another prime (81910603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40958801 + 40958802.

It is an arithmetic number, because the mean of its divisors is an integer number (40958802).

Almost surely, 2^81917603 is an apocalyptic number.

81917603 is a deficient number, since it is larger than the sum of its proper divisors (1).

81917603 is an equidigital number, since it uses as much as digits as its factorization.

81917603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 81917603 is about 9050.8343814258. The cubic root of 81917603 is about 434.3025826379.

The spelling of 81917603 in words is "eighty-one million, nine hundred seventeen thousand, six hundred three".