645464549 has 2 divisors, whose sum is σ = 645464550. Its totient is φ = 645464548.

The previous prime is 645464527. The next prime is 645464563. The reversal of 645464549 is 945464546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 443313025 + 202151524 = 21055^2 + 14218^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645464549 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645464849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322732274 + 322732275.

It is an arithmetic number, because the mean of its divisors is an integer number (322732275).

Almost surely, 2^645464549 is an apocalyptic number.

It is an amenable number.

645464549 is a deficient number, since it is larger than the sum of its proper divisors (1).

645464549 is an equidigital number, since it uses as much as digits as its factorization.

645464549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2073600, while the sum is 47.

The square root of 645464549 is about 25405.9943517273. The cubic root of 645464549 is about 864.2196394656.

The spelling of 645464549 in words is "six hundred forty-five million, four hundred sixty-four thousand, five hundred forty-nine".