645577 has 2 divisors, whose sum is σ = 645578. Its totient is φ = 645576.

The previous prime is 645571. The next prime is 645581. The reversal of 645577 is 775546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 404496 + 241081 = 636^2 + 491^2 .

It is a cyclic number.

It is not a de Polignac number, because 645577 - 2¹⁵ = 612809 is a prime.

It is not a weakly prime, because it can be changed into another prime (645571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322788 + 322789.

It is an arithmetic number, because the mean of its divisors is an integer number (322789).

2⁶⁴⁵⁵⁷⁷ is an apocalyptic number.

It is an amenable number.

645577 is a deficient number, since it is larger than the sum of its proper divisors (1).

645577 is an equidigital number, since it uses as much as digits as its factorization.

645577 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29400, while the sum is 34.

The square root of 645577 is about 803.4780644174. The cubic root of 645577 is about 86.4269823848.

The spelling of 645577 in words is "six hundred forty-five thousand, five hundred seventy-seven".