623905 has 4 divisors (see below), whose sum is σ = 748692. Its totient is φ = 499120.

The previous prime is 623893. The next prime is 623923. The reversal of 623905 is 509326.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 509326 = 2 ⋅254663.

It can be written as a sum of positive squares in 2 ways, for example, as 305809 + 318096 = 553^2 + 564^2 .

It is not a de Polignac number, because 623905 - 2⁹ = 623393 is a prime.

It is a d-powerful number, because it can be written as 6⁵ + 2 + 9⁴ + 3¹² + 0 + 5⁷ .

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 623905.

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, 62386 + ... + 62395.

It is an arithmetic number, because the mean of its divisors is an integer number (187173).

2⁶²³⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

623905 is a deficient number, since it is larger than the sum of its proper divisors (124787).

623905 is a wasteful number, since it uses less digits than its factorization.

623905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124786.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 623905 is about 789.8765726365. The cubic root of 623905 is about 85.4488368479.

The spelling of 623905 in words is "six hundred twenty-three thousand, nine hundred five".