628868861 has 2 divisors, whose sum is σ = 628868862. Its totient is φ = 628868860.

The previous prime is 628868827. The next prime is 628868873. The reversal of 628868861 is 168868826.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 541446361 + 87422500 = 23269^2 + 9350^2 .

It is a cyclic number.

It is not a de Polignac number, because 628868861 - 2²⁶ = 561759997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (628868881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314434430 + 314434431.

It is an arithmetic number, because the mean of its divisors is an integer number (314434431).

Almost surely, 2^628868861 is an apocalyptic number.

It is an amenable number.

628868861 is a deficient number, since it is larger than the sum of its proper divisors (1).

628868861 is an equidigital number, since it uses as much as digits as its factorization.

628868861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1769472, while the sum is 53.

The square root of 628868861 is about 25077.2578445092. The cubic root of 628868861 is about 856.7485214186.

The spelling of 628868861 in words is "six hundred twenty-eight million, eight hundred sixty-eight thousand, eight hundred sixty-one".