80521709 has 2 divisors, whose sum is σ = 80521710. Its totient is φ = 80521708.

The previous prime is 80521687. The next prime is 80521711. The reversal of 80521709 is 90712508.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79477225 + 1044484 = 8915^2 + 1022^2 .

It is a cyclic number.

It is not a de Polignac number, because 80521709 - 2⁸ = 80521453 is a prime.

Together with 80521711, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_4698104 and since 80521709 and 4698104 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 (80521789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40260854 + 40260855.

It is an arithmetic number, because the mean of its divisors is an integer number (40260855).

Almost surely, 2^80521709 is an apocalyptic number.

It is an amenable number.

80521709 is a deficient number, since it is larger than the sum of its proper divisors (1).

80521709 is an equidigital number, since it uses as much as digits as its factorization.

80521709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 80521709 is about 8973.3889361824. The cubic root of 80521709 is about 431.8215658984.

The spelling of 80521709 in words is "eighty million, five hundred twenty-one thousand, seven hundred nine".