644142 has 8 divisors (see below), whose sum is σ = 1288296. Its totient is φ = 214712.

The previous prime is 644141. The next prime is 644143. The reversal of 644142 is 241446.

644142 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (644141) and next prime (644143).

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

644142 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53673 + ... + 53684.

It is an arithmetic number, because the mean of its divisors is an integer number (161037).

2⁶⁴⁴¹⁴² is an apocalyptic number.

644142 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

644142 is a wasteful number, since it uses less digits than its factorization.

644142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107362.

The product of its digits is 768, while the sum is 21.

The square root of 644142 is about 802.5845749826. The cubic root of 644142 is about 86.3628977356.

Adding to 644142 its reverse (241446), we get a palindrome (885588).

The spelling of 644142 in words is "six hundred forty-four thousand, one hundred forty-two".