820043969 has 2 divisors, whose sum is σ = 820043970. Its totient is φ = 820043968.

The previous prime is 820043963. The next prime is 820044019. The reversal of 820043969 is 969340028.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 458473744 + 361570225 = 21412^2 + 19015^2 .

It is a cyclic number.

It is not a de Polignac number, because 820043969 - 2¹⁶ = 819978433 is a prime.

It is a super-2 number, since 2×820043969² = 1344944222186545922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (820043963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410021984 + 410021985.

It is an arithmetic number, because the mean of its divisors is an integer number (410021985).

Almost surely, 2^820043969 is an apocalyptic number.

It is an amenable number.

820043969 is a deficient number, since it is larger than the sum of its proper divisors (1).

820043969 is an equidigital number, since it uses as much as digits as its factorization.

820043969 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 93312, while the sum is 41.

The square root of 820043969 is about 28636.4098483033. The cubic root of 820043969 is about 936.0068915076.

The spelling of 820043969 in words is "eight hundred twenty million, forty-three thousand, nine hundred sixty-nine".