645406225 has 12 divisors (see below), whose sum is σ = 801243484. Its totient is φ = 515718720.

The previous prime is 645406219. The next prime is 645406247. The reversal of 645406225 is 522604546.

It can be written as a sum of positive squares in 6 ways, for example, as 79156609 + 566249616 = 8897^2 + 23796^2 .

It is not a de Polignac number, because 645406225 - 2³ = 645406217 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7207 + ... + 36643.

Almost surely, 2^645406225 is an apocalyptic number.

It is an amenable number.

645406225 is a deficient number, since it is larger than the sum of its proper divisors (155837259).

645406225 is a wasteful number, since it uses less digits than its factorization.

645406225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30324 (or 30319 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 34.

The square root of 645406225 is about 25404.8464864482. The cubic root of 645406225 is about 864.1936084648.

The spelling of 645406225 in words is "six hundred forty-five million, four hundred six thousand, two hundred twenty-five".