628305581 has 2 divisors, whose sum is σ = 628305582. Its totient is φ = 628305580.

The previous prime is 628305577. The next prime is 628305583. The reversal of 628305581 is 185503826.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 628304356 + 1225 = 25066^2 + 35^2 .

It is a cyclic number.

It is not a de Polignac number, because 628305581 - 2² = 628305577 is a prime.

It is a super-2 number, since 2×628305581² = 789535806231495122, which contains 22 as substring.

Together with 628305583, 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 (628305583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314152790 + 314152791.

It is an arithmetic number, because the mean of its divisors is an integer number (314152791).

Almost surely, 2^628305581 is an apocalyptic number.

It is an amenable number.

628305581 is a deficient number, since it is larger than the sum of its proper divisors (1).

628305581 is an equidigital number, since it uses as much as digits as its factorization.

628305581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 57600, while the sum is 38.

The square root of 628305581 is about 25066.0244354784. The cubic root of 628305581 is about 856.4926474760.

The spelling of 628305581 in words is "six hundred twenty-eight million, three hundred five thousand, five hundred eighty-one".