820684769 has 2 divisors, whose sum is σ = 820684770. Its totient is φ = 820684768.

The previous prime is 820684751. The next prime is 820684817. The reversal of 820684769 is 967486028.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 792985600 + 27699169 = 28160^2 + 5263^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820684769 is a prime.

It is a super-2 number, since 2×820684769² = 1347046980137166722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (820684069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410342384 + 410342385.

It is an arithmetic number, because the mean of its divisors is an integer number (410342385).

Almost surely, 2^820684769 is an apocalyptic number.

It is an amenable number.

820684769 is a deficient number, since it is larger than the sum of its proper divisors (1).

820684769 is an equidigital number, since it uses as much as digits as its factorization.

820684769 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1161216, while the sum is 50.

The square root of 820684769 is about 28647.5962167858. The cubic root of 820684769 is about 936.2506333377.

The spelling of 820684769 in words is "eight hundred twenty million, six hundred eighty-four thousand, seven hundred sixty-nine".