81734509 has 2 divisors, whose sum is σ = 81734510. Its totient is φ = 81734508.

The previous prime is 81734489. The next prime is 81734519. The reversal of 81734509 is 90543718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53144100 + 28590409 = 7290^2 + 5347^2 .

It is a cyclic number.

It is not a de Polignac number, because 81734509 - 2¹³ = 81726317 is a prime.

It is a super-2 number, since 2×81734509² = 13361059922942162, which contains 22 as substring.

It is a Chen prime.

It is equal to p_4764826 and since 81734509 and 4764826 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81734519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40867254 + 40867255.

It is an arithmetic number, because the mean of its divisors is an integer number (40867255).

Almost surely, 2^81734509 is an apocalyptic number.

It is an amenable number.

81734509 is a deficient number, since it is larger than the sum of its proper divisors (1).

81734509 is an equidigital number, since it uses as much as digits as its factorization.

81734509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 81734509 is about 9040.7139651689. The cubic root of 81734509 is about 433.9787714280.

The spelling of 81734509 in words is "eighty-one million, seven hundred thirty-four thousand, five hundred nine".