628220981 has 2 divisors, whose sum is σ = 628220982. Its totient is φ = 628220980.

The previous prime is 628220977. The next prime is 628220987. The reversal of 628220981 is 189022826.

628220981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 352162756 + 276058225 = 18766^2 + 16615^2 .

It is a cyclic number.

It is not a de Polignac number, because 628220981 - 2² = 628220977 is a prime.

It is a super-2 number, since 2×628220981² = 789323201937204722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (628220987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314110490 + 314110491.

It is an arithmetic number, because the mean of its divisors is an integer number (314110491).

Almost surely, 2^628220981 is an apocalyptic number.

It is an amenable number.

628220981 is a deficient number, since it is larger than the sum of its proper divisors (1).

628220981 is an equidigital number, since it uses as much as digits as its factorization.

628220981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 628220981 is about 25064.3368354321. The cubic root of 628220981 is about 856.4542041173.

The spelling of 628220981 in words is "six hundred twenty-eight million, two hundred twenty thousand, nine hundred eighty-one".