644413 has 8 divisors (see below), whose sum is σ = 803520. Its totient is φ = 502080.

The previous prime is 644411. The next prime is 644431. The reversal of 644413 is 314446.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 644413 - 2¹ = 644411 is a prime.

It is a super-2 number, since 2×644413² = 830536229138, which contains 22 as substring.

It is a Duffinian number.

644413 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644411) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4108 + ... + 4261.

It is an arithmetic number, because the mean of its divisors is an integer number (100440).

2⁶⁴⁴⁴¹³ is an apocalyptic number.

It is an amenable number.

644413 is a deficient number, since it is larger than the sum of its proper divisors (159107).

644413 is a wasteful number, since it uses less digits than its factorization.

644413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8387.

The product of its digits is 1152, while the sum is 22.

The square root of 644413 is about 802.7533867882. The cubic root of 644413 is about 86.3750074174.

Adding to 644413 its reverse (314446), we get a palindrome (958859).

The spelling of 644413 in words is "six hundred forty-four thousand, four hundred thirteen".