820985131709 has 2 divisors, whose sum is σ = 820985131710. Its totient is φ = 820985131708.

The previous prime is 820985131667. The next prime is 820985131739. The reversal of 820985131709 is 907131589028.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 610776636484 + 210208495225 = 781522^2 + 458485^2 .

It is a cyclic number.

It is not a de Polignac number, because 820985131709 - 2⁸ = 820985131453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820985131739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410492565854 + 410492565855.

It is an arithmetic number, because the mean of its divisors is an integer number (410492565855).

Almost surely, 2^820985131709 is an apocalyptic number.

It is an amenable number.

820985131709 is a deficient number, since it is larger than the sum of its proper divisors (1).

820985131709 is an equidigital number, since it uses as much as digits as its factorization.

820985131709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1088640, while the sum is 53.

The spelling of 820985131709 in words is "eight hundred twenty billion, nine hundred eighty-five million, one hundred thirty-one thousand, seven hundred nine".