644102 has 4 divisors (see below), whose sum is σ = 966156. Its totient is φ = 322050.

The previous prime is 644101. The next prime is 644107. The reversal of 644102 is 201446.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161024 + ... + 161027.

It is an arithmetic number, because the mean of its divisors is an integer number (241539).

2⁶⁴⁴¹⁰² is an apocalyptic number.

644102 is a deficient number, since it is larger than the sum of its proper divisors (322054).

644102 is a wasteful number, since it uses less digits than its factorization.

644102 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322053.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 644102 is about 802.5596551036. The cubic root of 644102 is about 86.3611100411.

Adding to 644102 its reverse (201446), we get a palindrome (845548).

The spelling of 644102 in words is "six hundred forty-four thousand, one hundred two".