643604 has 12 divisors (see below), whose sum is σ = 1213044. Its totient is φ = 297024.

The previous prime is 643589. The next prime is 643619. The reversal of 643604 is 406346.

It is an interprime number because it is at equal distance from previous prime (643589) and next prime (643619).

It can be written as a sum of positive squares in 2 ways, for example, as 84100 + 559504 = 290^2 + 748^2 .

It is a super-2 number, since 2×643604² = 828452217632, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 643604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6137 + ... + 6240.

It is an arithmetic number, because the mean of its divisors is an integer number (101087).

2⁶⁴³⁶⁰⁴ is an apocalyptic number.

It is an amenable number.

643604 is a deficient number, since it is larger than the sum of its proper divisors (569440).

643604 is a wasteful number, since it uses less digits than its factorization.

643604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12394 (or 12392 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 23.

The square root of 643604 is about 802.2493377997. The cubic root of 643604 is about 86.3388470446.

The spelling of 643604 in words is "six hundred forty-three thousand, six hundred four".