645023 has 2 divisors, whose sum is σ = 645024. Its totient is φ = 645022.

The previous prime is 645019. The next prime is 645037. The reversal of 645023 is 320546.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 645023 - 2² = 645019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644986 and 645004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322511 + 322512.

It is an arithmetic number, because the mean of its divisors is an integer number (322512).

2⁶⁴⁵⁰²³ is an apocalyptic number.

645023 is a deficient number, since it is larger than the sum of its proper divisors (1).

645023 is an equidigital number, since it uses as much as digits as its factorization.

645023 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 645023 is about 803.1332392573. The cubic root of 645023 is about 86.4022529562.

Adding to 645023 its reverse (320546), we get a palindrome (965569).

The spelling of 645023 in words is "six hundred forty-five thousand, twenty-three".