82521709 has 2 divisors, whose sum is σ = 82521710. Its totient is φ = 82521708.

The previous prime is 82521697. The next prime is 82521727. The reversal of 82521709 is 90712528.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66879684 + 15642025 = 8178^2 + 3955^2 .

It is a cyclic number.

It is not a de Polignac number, because 82521709 - 2²¹ = 80424557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (82521739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41260854 + 41260855.

It is an arithmetic number, because the mean of its divisors is an integer number (41260855).

Almost surely, 2^82521709 is an apocalyptic number.

It is an amenable number.

82521709 is a deficient number, since it is larger than the sum of its proper divisors (1).

82521709 is an equidigital number, since it uses as much as digits as its factorization.

82521709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 82521709 is about 9084.1460248061. The cubic root of 82521709 is about 435.3675653134.

The spelling of 82521709 in words is "eighty-two million, five hundred twenty-one thousand, seven hundred nine".