645722 has 24 divisors (see below), whose sum is σ = 1231200. Its totient is φ = 251160.

The previous prime is 645713. The next prime is 645727. The reversal of 645722 is 227546.

It is a junction number, because it is equal to n+sod(n) for n = 645691 and 645700.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 779 + ... + 1377.

It is an arithmetic number, because the mean of its divisors is an integer number (51300).

2⁶⁴⁵⁷²² is an apocalyptic number.

645722 is a deficient number, since it is larger than the sum of its proper divisors (585478).

645722 is a wasteful number, since it uses less digits than its factorization.

645722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 626 (or 619 counting only the distinct ones).

The product of its digits is 3360, while the sum is 26.

The square root of 645722 is about 803.5682920574. The cubic root of 645722 is about 86.4334525525.

The spelling of 645722 in words is "six hundred forty-five thousand, seven hundred twenty-two".