820820999 has 2 divisors, whose sum is σ = 820821000. Its totient is φ = 820820998.

The previous prime is 820820971. The next prime is 820821011. The reversal of 820820999 is 999028028.

It is a happy number.

820820999 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820820999 is a prime.

It is a super-3 number, since 3×820820999³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820820929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410410499 + 410410500.

It is an arithmetic number, because the mean of its divisors is an integer number (410410500).

Almost surely, 2^820820999 is an apocalyptic number.

820820999 is a deficient number, since it is larger than the sum of its proper divisors (1).

820820999 is an equidigital number, since it uses as much as digits as its factorization.

820820999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 47.

The square root of 820820999 is about 28649.9738045255. The cubic root of 820820999 is about 936.3024349437.

The spelling of 820820999 in words is "eight hundred twenty million, eight hundred twenty thousand, nine hundred ninety-nine".