645203677 has 2 divisors, whose sum is σ = 645203678. Its totient is φ = 645203676.

The previous prime is 645203627. The next prime is 645203681. The reversal of 645203677 is 776302546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 432889636 + 212314041 = 20806^2 + 14571^2 .

It is a cyclic number.

It is not a de Polignac number, because 645203677 - 2⁷ = 645203549 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 (645203627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322601838 + 322601839.

It is an arithmetic number, because the mean of its divisors is an integer number (322601839).

Almost surely, 2^645203677 is an apocalyptic number.

It is an amenable number.

645203677 is a deficient number, since it is larger than the sum of its proper divisors (1).

645203677 is an equidigital number, since it uses as much as digits as its factorization.

645203677 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 211680, while the sum is 40.

The square root of 645203677 is about 25400.8597689133. The cubic root of 645203677 is about 864.1031956393.

The spelling of 645203677 in words is "six hundred forty-five million, two hundred three thousand, six hundred seventy-seven".