820999769 has 2 divisors, whose sum is σ = 820999770. Its totient is φ = 820999768.

The previous prime is 820999759. The next prime is 820999783. The reversal of 820999769 is 967999028.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 796368400 + 24631369 = 28220^2 + 4963^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820999769 is a prime.

It is a super-2 number, since 2×820999769² = 1348081241396106722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (820999759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410499884 + 410499885.

It is an arithmetic number, because the mean of its divisors is an integer number (410499885).

Almost surely, 2^820999769 is an apocalyptic number.

It is an amenable number.

820999769 is a deficient number, since it is larger than the sum of its proper divisors (1).

820999769 is an equidigital number, since it uses as much as digits as its factorization.

820999769 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4408992, while the sum is 59.

The square root of 820999769 is about 28653.0935328107. The cubic root of 820999769 is about 936.3704037360.

The spelling of 820999769 in words is "eight hundred twenty million, nine hundred ninety-nine thousand, seven hundred sixty-nine".