645730 has 16 divisors (see below), whose sum is σ = 1200384. Its totient is φ = 249840.

The previous prime is 645727. The next prime is 645737. The reversal of 645730 is 37546.

645730 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 645695 and 645704.

It is not an unprimeable number, because it can be changed into a prime (645737) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 732 + ... + 1351.

It is an arithmetic number, because the mean of its divisors is an integer number (75024).

2⁶⁴⁵⁷³⁰ is an apocalyptic number.

645730 is a deficient number, since it is larger than the sum of its proper divisors (554654).

645730 is a wasteful number, since it uses less digits than its factorization.

645730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2121.

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 645730 is about 803.5732698392. The cubic root of 645730 is about 86.4338094991.

The spelling of 645730 in words is "six hundred forty-five thousand, seven hundred thirty".