628210721 has 2 divisors, whose sum is σ = 628210722. Its totient is φ = 628210720.

The previous prime is 628210669. The next prime is 628210729. The reversal of 628210721 is 127012826.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 360430225 + 267780496 = 18985^2 + 16364^2 .

It is a cyclic number.

It is not a de Polignac number, because 628210721 - 2⁶ = 628210657 is a prime.

It is not a weakly prime, because it can be changed into another prime (628210729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314105360 + 314105361.

It is an arithmetic number, because the mean of its divisors is an integer number (314105361).

Almost surely, 2^628210721 is an apocalyptic number.

It is an amenable number.

628210721 is a deficient number, since it is larger than the sum of its proper divisors (1).

628210721 is an equidigital number, since it uses as much as digits as its factorization.

628210721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 628210721 is about 25064.1321613177. The cubic root of 628210721 is about 856.4495416030.

The spelling of 628210721 in words is "six hundred twenty-eight million, two hundred ten thousand, seven hundred twenty-one".