645504469 has 2 divisors, whose sum is σ = 645504470. Its totient is φ = 645504468.

The previous prime is 645504397. The next prime is 645504473. The reversal of 645504469 is 964405546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 388287025 + 257217444 = 19705^2 + 16038^2 .

It is a cyclic number.

It is not a de Polignac number, because 645504469 - 2⁷ = 645504341 is a prime.

It is a super-2 number, since 2×645504469² = 833352038997943922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645504869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322752234 + 322752235.

It is an arithmetic number, because the mean of its divisors is an integer number (322752235).

Almost surely, 2^645504469 is an apocalyptic number.

It is an amenable number.

645504469 is a deficient number, since it is larger than the sum of its proper divisors (1).

645504469 is an equidigital number, since it uses as much as digits as its factorization.

645504469 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 518400, while the sum is 43.

The square root of 645504469 is about 25406.7799809421. The cubic root of 645504469 is about 864.2374555418.

The spelling of 645504469 in words is "six hundred forty-five million, five hundred four thousand, four hundred sixty-nine".