81739663 has 2 divisors, whose sum is σ = 81739664. Its totient is φ = 81739662.

The previous prime is 81739657. The next prime is 81739699. The reversal of 81739663 is 36693718.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81739663 - 2²⁵ = 48185231 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81739643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40869831 + 40869832.

It is an arithmetic number, because the mean of its divisors is an integer number (40869832).

Almost surely, 2^81739663 is an apocalyptic number.

81739663 is a deficient number, since it is larger than the sum of its proper divisors (1).

81739663 is an equidigital number, since it uses as much as digits as its factorization.

81739663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 43.

The square root of 81739663 is about 9040.9990045348. Note that the first 3 decimals coincide. The cubic root of 81739663 is about 433.9878931547.

The spelling of 81739663 in words is "eighty-one million, seven hundred thirty-nine thousand, six hundred sixty-three".