646939225 has 9 divisors (see below), whose sum is σ = 802362367. Its totient is φ = 517449640.

The previous prime is 646939211. The next prime is 646939243. The reversal of 646939225 is 522939646.

The square root of 646939225 is 25435.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 232898121 + 414041104 = 15261^2 + 20348^2 .

It is not a de Polignac number, because 646939225 - 2¹¹ = 646937177 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 124632 + ... + 129718.

Almost surely, 2^646939225 is an apocalyptic number.

646939225 is the 25435-th square number.

646939225 is the 12718-th centered octagonal number.

It is an amenable number.

646939225 is a deficient number, since it is larger than the sum of its proper divisors (155423142).

646939225 is an frugal number, since it uses more digits than its factorization.

646939225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10184 (or 5092 counting only the distinct ones).

The product of its digits is 699840, while the sum is 46.

The cubic root of 646939225 is about 864.8772922265.

The spelling of 646939225 in words is "six hundred forty-six million, nine hundred thirty-nine thousand, two hundred twenty-five".