630907721 has 4 divisors (see below), whose sum is σ = 631290132. Its totient is φ = 630525312.

The previous prime is 630907699. The next prime is 630907751. The reversal of 630907721 is 127709036.

630907721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 486643600 + 144264121 = 22060^2 + 12011^2 .

It is a cyclic number.

It is not a de Polignac number, because 630907721 - 2⁶ = 630907657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (630907751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 188720 + ... + 192033.

It is an arithmetic number, because the mean of its divisors is an integer number (157822533).

Almost surely, 2^630907721 is an apocalyptic number.

It is an amenable number.

630907721 is a deficient number, since it is larger than the sum of its proper divisors (382411).

630907721 is a wasteful number, since it uses less digits than its factorization.

630907721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382410.

The product of its (nonzero) digits is 15876, while the sum is 35.

The square root of 630907721 is about 25117.8765225088. The cubic root of 630907721 is about 857.6734126697.

The spelling of 630907721 in words is "six hundred thirty million, nine hundred seven thousand, seven hundred twenty-one".