630139781 has 2 divisors, whose sum is σ = 630139782. Its totient is φ = 630139780.

The previous prime is 630139777. The next prime is 630139793. The reversal of 630139781 is 187931036.

630139781 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., 442723681 + 187416100 = 21041^2 + 13690^2 .

It is a cyclic number.

It is not a de Polignac number, because 630139781 - 2² = 630139777 is a prime.

It is a super-2 number, since 2×630139781² = 794152287197455922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (630132781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315069890 + 315069891.

It is an arithmetic number, because the mean of its divisors is an integer number (315069891).

Almost surely, 2^630139781 is an apocalyptic number.

It is an amenable number.

630139781 is a deficient number, since it is larger than the sum of its proper divisors (1).

630139781 is an equidigital number, since it uses as much as digits as its factorization.

630139781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27216, while the sum is 38.

The square root of 630139781 is about 25102.5851457574. The cubic root of 630139781 is about 857.3252850899.

The spelling of 630139781 in words is "six hundred thirty million, one hundred thirty-nine thousand, seven hundred eighty-one".