628861 has 2 divisors, whose sum is σ = 628862. Its totient is φ = 628860.

The previous prime is 628841. The next prime is 628877. The reversal of 628861 is 168826.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 624100 + 4761 = 790^2 + 69^2 .

It is a cyclic number.

It is not a de Polignac number, because 628861 - 2¹⁵ = 596093 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (628801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314430 + 314431.

It is an arithmetic number, because the mean of its divisors is an integer number (314431).

2⁶²⁸⁸⁶¹ is an apocalyptic number.

It is an amenable number.

628861 is a deficient number, since it is larger than the sum of its proper divisors (1).

628861 is an equidigital number, since it uses as much as digits as its factorization.

628861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4608, while the sum is 31.

The square root of 628861 is about 793.0075661682. The cubic root of 628861 is about 85.6744951555.

It can be divided in two parts, 6 and 28861, that multiplied together give a triangular number (173166 = T₅₈₈).

The spelling of 628861 in words is "six hundred twenty-eight thousand, eight hundred sixty-one".