645397 has 2 divisors, whose sum is σ = 645398. Its totient is φ = 645396.

The previous prime is 645383. The next prime is 645409. The reversal of 645397 is 793546.

645397 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 505521 + 139876 = 711^2 + 374^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322698 + 322699.

It is an arithmetic number, because the mean of its divisors is an integer number (322699).

2⁶⁴⁵³⁹⁷ is an apocalyptic number.

It is an amenable number.

645397 is a deficient number, since it is larger than the sum of its proper divisors (1).

645397 is an equidigital number, since it uses as much as digits as its factorization.

645397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22680, while the sum is 34.

The square root of 645397 is about 803.3660435941. The cubic root of 645397 is about 86.4189491046.

It can be divided in two parts, 64539 and 7, that added together give a palindrome (64546).

The spelling of 645397 in words is "six hundred forty-five thousand, three hundred ninety-seven".