630639721 has 2 divisors, whose sum is σ = 630639722. Its totient is φ = 630639720.

The previous prime is 630639689. The next prime is 630639791. The reversal of 630639721 is 127936036.

630639721 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., 332697600 + 297942121 = 18240^2 + 17261^2 .

It is a cyclic number.

It is not a de Polignac number, because 630639721 - 2⁵ = 630639689 is a prime.

It is not a weakly prime, because it can be changed into another prime (630639791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315319860 + 315319861.

It is an arithmetic number, because the mean of its divisors is an integer number (315319861).

Almost surely, 2^630639721 is an apocalyptic number.

It is an amenable number.

630639721 is a deficient number, since it is larger than the sum of its proper divisors (1).

630639721 is an equidigital number, since it uses as much as digits as its factorization.

630639721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40824, while the sum is 37.

The square root of 630639721 is about 25112.5411099713. The cubic root of 630639721 is about 857.5519532650.

The spelling of 630639721 in words is "six hundred thirty million, six hundred thirty-nine thousand, seven hundred twenty-one".