645738 has 16 divisors (see below), whose sum is σ = 1299456. Its totient is φ = 213920.

The previous prime is 645737. The next prime is 645739. The reversal of 645738 is 837546.

It is an interprime number because it is at equal distance from previous prime (645737) and next prime (645739).

It is a junction number, because it is equal to n+sod(n) for n = 645699 and 645708.

It is not an unprimeable number, because it can be changed into a prime (645737) 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 7 ways as a sum of consecutive naturals, for example, 1495 + ... + 1877.

It is an arithmetic number, because the mean of its divisors is an integer number (81216).

2⁶⁴⁵⁷³⁸ is an apocalyptic number.

645738 is an abundant number, since it is smaller than the sum of its proper divisors (653718).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645738 is a wasteful number, since it uses less digits than its factorization.

645738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 669.

The product of its digits is 20160, while the sum is 33.

The square root of 645738 is about 803.5782475901. The cubic root of 645738 is about 86.4341664427.

The spelling of 645738 in words is "six hundred forty-five thousand, seven hundred thirty-eight".