623440 has 20 divisors (see below), whose sum is σ = 1449684. Its totient is φ = 249344.

The previous prime is 623437. The next prime is 623477. The reversal of 623440 is 44326.

It can be written as a sum of positive squares in 2 ways, for example, as 456976 + 166464 = 676^2 + 408^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3817 + ... + 3976.

2⁶²³⁴⁴⁰ is an apocalyptic number.

It is an amenable number.

623440 is an abundant number, since it is smaller than the sum of its proper divisors (826244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

623440 is a wasteful number, since it uses less digits than its factorization.

623440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7806 (or 7800 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 623440 is about 789.5821679851. The cubic root of 623440 is about 85.4276030679.

Adding to 623440 its reverse (44326), we get a palindrome (667766).

The spelling of 623440 in words is "six hundred twenty-three thousand, four hundred forty".