643624 has 16 divisors (see below), whose sum is σ = 1235520. Its totient is φ = 314160.

The previous prime is 643619. The next prime is 643633. The reversal of 643624 is 426346.

It is a nialpdrome in base 15.

It is a congruent number.

It is an unprimeable number.

643624 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, 592 + ... + 1279.

It is an arithmetic number, because the mean of its divisors is an integer number (77220).

2⁶⁴³⁶²⁴ is an apocalyptic number.

It is an amenable number.

643624 is a deficient number, since it is larger than the sum of its proper divisors (591896).

643624 is a wasteful number, since it uses less digits than its factorization.

643624 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1920 (or 1916 counting only the distinct ones).

The product of its digits is 3456, while the sum is 25.

The square root of 643624 is about 802.2618026555. The cubic root of 643624 is about 86.3397413622.

The spelling of 643624 in words is "six hundred forty-three thousand, six hundred twenty-four".