645563353 has 2 divisors, whose sum is σ = 645563354. Its totient is φ = 645563352.

The previous prime is 645563351. The next prime is 645563381. The reversal of 645563353 is 353365546.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 643789129 + 1774224 = 25373^2 + 1332^2 .

It is a cyclic number.

It is not a de Polignac number, because 645563353 - 2¹ = 645563351 is a prime.

Together with 645563351, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (645563351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322781676 + 322781677.

It is an arithmetic number, because the mean of its divisors is an integer number (322781677).

Almost surely, 2^645563353 is an apocalyptic number.

It is an amenable number.

645563353 is a deficient number, since it is larger than the sum of its proper divisors (1).

645563353 is an equidigital number, since it uses as much as digits as its factorization.

645563353 is an evil number, because the sum of its binary digits is even.

The product of its digits is 486000, while the sum is 40.

The square root of 645563353 is about 25407.9387790509. The cubic root of 645563353 is about 864.2637338060.

The spelling of 645563353 in words is "six hundred forty-five million, five hundred sixty-three thousand, three hundred fifty-three".