645442177 has 2 divisors, whose sum is σ = 645442178. Its totient is φ = 645442176.

The previous prime is 645442157. The next prime is 645442181. The reversal of 645442177 is 771244546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 645363216 + 78961 = 25404^2 + 281^2 .

It is a cyclic number.

It is not a de Polignac number, because 645442177 - 2¹¹ = 645440129 is a prime.

It is not a weakly prime, because it can be changed into another prime (645442157) by changing a digit.

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 as a sum of consecutive naturals, namely, 322721088 + 322721089.

It is an arithmetic number, because the mean of its divisors is an integer number (322721089).

Almost surely, 2^645442177 is an apocalyptic number.

It is an amenable number.

645442177 is a deficient number, since it is larger than the sum of its proper divisors (1).

645442177 is an equidigital number, since it uses as much as digits as its factorization.

645442177 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 188160, while the sum is 40.

The square root of 645442177 is about 25405.5540581189. The cubic root of 645442177 is about 864.2096546439.

The spelling of 645442177 in words is "six hundred forty-five million, four hundred forty-two thousand, one hundred seventy-seven".