855620561 has 2 divisors, whose sum is σ = 855620562. Its totient is φ = 855620560.

The previous prime is 855620551. The next prime is 855620573. The reversal of 855620561 is 165026558.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 762864400 + 92756161 = 27620^2 + 9631^2 .

It is a cyclic number.

It is not a de Polignac number, because 855620561 - 2¹⁴ = 855604177 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (855620551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 427810280 + 427810281.

It is an arithmetic number, because the mean of its divisors is an integer number (427810281).

Almost surely, 2^855620561 is an apocalyptic number.

It is an amenable number.

855620561 is a deficient number, since it is larger than the sum of its proper divisors (1).

855620561 is an equidigital number, since it uses as much as digits as its factorization.

855620561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72000, while the sum is 38.

The square root of 855620561 is about 29250.9924788886. The cubic root of 855620561 is about 949.3515652594.

The spelling of 855620561 in words is "eight hundred fifty-five million, six hundred twenty thousand, five hundred sixty-one".