81905683 has 2 divisors, whose sum is σ = 81905684. Its totient is φ = 81905682.

The previous prime is 81905653. The next prime is 81905687. The reversal of 81905683 is 38650918.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81905683 - 2¹⁷ = 81774611 is a prime.

It is not a weakly prime, because it can be changed into another prime (81905687) 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, 40952841 + 40952842.

It is an arithmetic number, because the mean of its divisors is an integer number (40952842).

Almost surely, 2^81905683 is an apocalyptic number.

81905683 is a deficient number, since it is larger than the sum of its proper divisors (1).

81905683 is an equidigital number, since it uses as much as digits as its factorization.

81905683 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 81905683 is about 9050.1758546450. The cubic root of 81905683 is about 434.2815161935.

The spelling of 81905683 in words is "eighty-one million, nine hundred five thousand, six hundred eighty-three".