645493 has 2 divisors, whose sum is σ = 645494. Its totient is φ = 645492.

The previous prime is 645481. The next prime is 645497. The reversal of 645493 is 394546.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 528529 + 116964 = 727^2 + 342^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645493 is a prime.

It is a super-2 number, since 2×645493² = 833322426098, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322746 + 322747.

It is an arithmetic number, because the mean of its divisors is an integer number (322747).

2⁶⁴⁵⁴⁹³ is an apocalyptic number.

It is an amenable number.

645493 is a deficient number, since it is larger than the sum of its proper divisors (1).

645493 is an equidigital number, since it uses as much as digits as its factorization.

645493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12960, while the sum is 31.

The square root of 645493 is about 803.4257899769. The cubic root of 645493 is about 86.4232337065.

The spelling of 645493 in words is "six hundred forty-five thousand, four hundred ninety-three".