645723 has 12 divisors (see below), whose sum is σ = 1004640. Its totient is φ = 397296.

The previous prime is 645713. The next prime is 645727. The reversal of 645723 is 327546.

It is a happy number.

645723 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 645723 - 2⁵ = 645691 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

645723 is strictly pandigital in base 7.

It is not an unprimeable number, because it can be changed into a prime (645727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2643 + ... + 2876.

It is an arithmetic number, because the mean of its divisors is an integer number (83720).

2⁶⁴⁵⁷²³ is an apocalyptic number.

645723 is a deficient number, since it is larger than the sum of its proper divisors (358917).

645723 is a wasteful number, since it uses less digits than its factorization.

645723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5538 (or 5535 counting only the distinct ones).

The product of its digits is 5040, while the sum is 27.

The square root of 645723 is about 803.5689142818. The cubic root of 645723 is about 86.4334971710.

The spelling of 645723 in words is "six hundred forty-five thousand, seven hundred twenty-three".