81724829 has 2 divisors, whose sum is σ = 81724830. Its totient is φ = 81724828.

The previous prime is 81724801. The next prime is 81724837. The reversal of 81724829 is 92842718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77616100 + 4108729 = 8810^2 + 2027^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81724829 is a prime.

It is a Chen prime.

It is equal to p_4764299 and since 81724829 and 4764299 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 (81724229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40862414 + 40862415.

It is an arithmetic number, because the mean of its divisors is an integer number (40862415).

Almost surely, 2^81724829 is an apocalyptic number.

It is an amenable number.

81724829 is a deficient number, since it is larger than the sum of its proper divisors (1).

81724829 is an equidigital number, since it uses as much as digits as its factorization.

81724829 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64512, while the sum is 41.

The square root of 81724829 is about 9040.1785933686. The cubic root of 81724829 is about 433.9616383940.

The spelling of 81724829 in words is "eighty-one million, seven hundred twenty-four thousand, eight hundred twenty-nine".