820866539 has 8 divisors (see below), whose sum is σ = 869532048. Its totient is φ = 772243200.

The previous prime is 820866511. The next prime is 820866551. The reversal of 820866539 is 935668028.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 820866539 - 2²⁴ = 804089323 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 820866493 and 820866502.

It is not an unprimeable number, because it can be changed into a prime (820866559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35264 + ... + 53714.

It is an arithmetic number, because the mean of its divisors is an integer number (108691506).

Almost surely, 2^820866539 is an apocalyptic number.

820866539 is a deficient number, since it is larger than the sum of its proper divisors (48665509).

820866539 is a wasteful number, since it uses less digits than its factorization.

820866539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21085.

The product of its (nonzero) digits is 622080, while the sum is 47.

The square root of 820866539 is about 28650.7685586268. The cubic root of 820866539 is about 936.3197503001.

It can be divided in two parts, 8208 and 66539, that added together give a palindrome (74747).

The spelling of 820866539 in words is "eight hundred twenty million, eight hundred sixty-six thousand, five hundred thirty-nine".