645442 has 8 divisors (see below), whose sum is σ = 1106496. Its totient is φ = 276612.

The previous prime is 645433. The next prime is 645443. The reversal of 645442 is 244546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (645443) by changing a digit.

645442 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23038 + ... + 23065.

It is an arithmetic number, because the mean of its divisors is an integer number (138312).

2⁶⁴⁵⁴⁴² is an apocalyptic number.

645442 is a deficient number, since it is larger than the sum of its proper divisors (461054).

645442 is a wasteful number, since it uses less digits than its factorization.

645442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46112.

The product of its digits is 3840, while the sum is 25.

The square root of 645442 is about 803.3940502643. The cubic root of 645442 is about 86.4209575646.

Adding to 645442 its reverse (244546), we get a palindrome (889988).

It can be divided in two parts, 64544 and 2, that added together give a palindrome (64546).

The spelling of 645442 in words is "six hundred forty-five thousand, four hundred forty-two".