820199779 has 16 divisors (see below), whose sum is σ = 989496000. Its totient is φ = 678777792.

The previous prime is 820199741. The next prime is 820199789. The reversal of 820199779 is 977991028.

It is not a de Polignac number, because 820199779 - 2¹³ = 820191587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820199789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31282 + ... + 51175.

It is an arithmetic number, because the mean of its divisors is an integer number (61843500).

Almost surely, 2^820199779 is an apocalyptic number.

820199779 is a deficient number, since it is larger than the sum of its proper divisors (169296221).

820199779 is an equidigital number, since it uses as much as digits as its factorization.

820199779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82507 (or 82493 counting only the distinct ones).

The product of its (nonzero) digits is 571536, while the sum is 52.

The square root of 820199779 is about 28639.1302067643. The cubic root of 820199779 is about 936.0661688161.

The spelling of 820199779 in words is "eight hundred twenty million, one hundred ninety-nine thousand, seven hundred seventy-nine".