645734717 has 2 divisors, whose sum is σ = 645734718. Its totient is φ = 645734716.

The previous prime is 645734659. The next prime is 645734731. The reversal of 645734717 is 717437546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 541306756 + 104427961 = 23266^2 + 10219^2 .

It is a cyclic number.

It is not a de Polignac number, because 645734717 - 2⁶ = 645734653 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 (645734777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322867358 + 322867359.

It is an arithmetic number, because the mean of its divisors is an integer number (322867359).

Almost surely, 2^645734717 is an apocalyptic number.

It is an amenable number.

645734717 is a deficient number, since it is larger than the sum of its proper divisors (1).

645734717 is an equidigital number, since it uses as much as digits as its factorization.

645734717 is an evil number, because the sum of its binary digits is even.

The product of its digits is 493920, while the sum is 44.

The square root of 645734717 is about 25411.3108083782. The cubic root of 645734717 is about 864.3401996231.

The spelling of 645734717 in words is "six hundred forty-five million, seven hundred thirty-four thousand, seven hundred seventeen".