645472277 has 2 divisors, whose sum is σ = 645472278. Its totient is φ = 645472276.

The previous prime is 645472271. The next prime is 645472279. The reversal of 645472277 is 772274546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 512162161 + 133310116 = 22631^2 + 11546^2 .

It is a cyclic number.

It is not a de Polignac number, because 645472277 - 2⁸ = 645472021 is a prime.

Together with 645472279, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645472271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322736138 + 322736139.

It is an arithmetic number, because the mean of its divisors is an integer number (322736139).

Almost surely, 2^645472277 is an apocalyptic number.

It is an amenable number.

645472277 is a deficient number, since it is larger than the sum of its proper divisors (1).

645472277 is an equidigital number, since it uses as much as digits as its factorization.

645472277 is an evil number, because the sum of its binary digits is even.

The product of its digits is 658560, while the sum is 44.

The square root of 645472277 is about 25406.1464413634. The cubic root of 645472277 is about 864.2230884868.

The spelling of 645472277 in words is "six hundred forty-five million, four hundred seventy-two thousand, two hundred seventy-seven".