645863797 has 2 divisors, whose sum is σ = 645863798. Its totient is φ = 645863796.

The previous prime is 645863767. The next prime is 645863809. The reversal of 645863797 is 797368546.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 526748401 + 119115396 = 22951^2 + 10914^2 .

It is a cyclic number.

It is not a de Polignac number, because 645863797 - 2¹⁹ = 645339509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645863717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322931898 + 322931899.

It is an arithmetic number, because the mean of its divisors is an integer number (322931899).

Almost surely, 2^645863797 is an apocalyptic number.

It is an amenable number.

645863797 is a deficient number, since it is larger than the sum of its proper divisors (1).

645863797 is an equidigital number, since it uses as much as digits as its factorization.

645863797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7620480, while the sum is 55.

The square root of 645863797 is about 25413.8504953500. The cubic root of 645863797 is about 864.3977885972.

The spelling of 645863797 in words is "six hundred forty-five million, eight hundred sixty-three thousand, seven hundred ninety-seven".