645848569 has 2 divisors, whose sum is σ = 645848570. Its totient is φ = 645848568.

The previous prime is 645848549. The next prime is 645848591. The reversal of 645848569 is 965848546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 475806969 + 170041600 = 21813^2 + 13040^2 .

It is a cyclic number.

It is not a de Polignac number, because 645848569 - 2⁵ = 645848537 is a prime.

It is a super-2 number, since 2×645848569² = 834240748158695522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (645848549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322924284 + 322924285.

It is an arithmetic number, because the mean of its divisors is an integer number (322924285).

Almost surely, 2^645848569 is an apocalyptic number.

It is an amenable number.

645848569 is a deficient number, since it is larger than the sum of its proper divisors (1).

645848569 is an equidigital number, since it uses as much as digits as its factorization.

645848569 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8294400, while the sum is 55.

The square root of 645848569 is about 25413.5508931751. The cubic root of 645848569 is about 864.3909950322.

It can be divided in two parts, 64584 and 8569, that added together give a triangular number (73153 = T₃₈₂).

The spelling of 645848569 in words is "six hundred forty-five million, eight hundred forty-eight thousand, five hundred sixty-nine".