630505921 has 4 divisors (see below), whose sum is σ = 635108292. Its totient is φ = 625903552.

The previous prime is 630505879. The next prime is 630505957. The reversal of 630505921 is 129505036.

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 248850625 + 381655296 = 15775^2 + 19536^2 .

It is a cyclic number.

It is not a de Polignac number, because 630505921 - 2⁷ = 630505793 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (630505021) 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, 2300980 + ... + 2301253.

It is an arithmetic number, because the mean of its divisors is an integer number (158777073).

Almost surely, 2^630505921 is an apocalyptic number.

It is an amenable number.

630505921 is a deficient number, since it is larger than the sum of its proper divisors (4602371).

630505921 is a wasteful number, since it uses less digits than its factorization.

630505921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4602370.

The product of its (nonzero) digits is 8100, while the sum is 31.

The square root of 630505921 is about 25109.8769610685. The cubic root of 630505921 is about 857.4913013253.

The spelling of 630505921 in words is "six hundred thirty million, five hundred five thousand, nine hundred twenty-one".