820556311 has 2 divisors, whose sum is σ = 820556312. Its totient is φ = 820556310.

The previous prime is 820556309. The next prime is 820556339. The reversal of 820556311 is 113655028.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 820556311 - 2¹ = 820556309 is a prime.

Together with 820556309, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820556371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410278155 + 410278156.

It is an arithmetic number, because the mean of its divisors is an integer number (410278156).

Almost surely, 2^820556311 is an apocalyptic number.

820556311 is a deficient number, since it is larger than the sum of its proper divisors (1).

820556311 is an equidigital number, since it uses as much as digits as its factorization.

820556311 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 820556311 is about 28645.3540910215. The cubic root of 820556311 is about 936.2017817916.

It can be divided in two parts, 8205 and 56311, that added together give a square (64516 = 254²).

The spelling of 820556311 in words is "eight hundred twenty million, five hundred fifty-six thousand, three hundred eleven".