820680449 has 4 divisors (see below), whose sum is σ = 828806100. Its totient is φ = 812554800.

The previous prime is 820680403. The next prime is 820680463. The reversal of 820680449 is 944086028.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 522945424 + 297735025 = 22868^2 + 17255^2 .

It is a cyclic number.

It is not a de Polignac number, because 820680449 - 2¹⁶ = 820614913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820682449) 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 3 ways as a sum of consecutive naturals, for example, 4062674 + ... + 4062875.

It is an arithmetic number, because the mean of its divisors is an integer number (207201525).

Almost surely, 2^820680449 is an apocalyptic number.

It is an amenable number.

820680449 is a deficient number, since it is larger than the sum of its proper divisors (8125651).

820680449 is a wasteful number, since it uses less digits than its factorization.

820680449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8125650.

The product of its (nonzero) digits is 110592, while the sum is 41.

The square root of 820680449 is about 28647.5208176903. The cubic root of 820680449 is about 936.2489905592.

The spelling of 820680449 in words is "eight hundred twenty million, six hundred eighty thousand, four hundred forty-nine".