624409 has 4 divisors (see below), whose sum is σ = 632016. Its totient is φ = 616804.

The previous prime is 624401. The next prime is 624419. The reversal of 624409 is 904426.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 904426 = 2 ⋅452213.

It is a cyclic number.

It is not a de Polignac number, because 624409 - 2³ = 624401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (624401) 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, 3679 + ... + 3844.

It is an arithmetic number, because the mean of its divisors is an integer number (158004).

2⁶²⁴⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

624409 is a deficient number, since it is larger than the sum of its proper divisors (7607).

624409 is an equidigital number, since it uses as much as digits as its factorization.

624409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7606.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 624409 is about 790.1955454190. The cubic root of 624409 is about 85.4718396141.

The spelling of 624409 in words is "six hundred twenty-four thousand, four hundred nine".