626409 has 24 divisors (see below), whose sum is σ = 1057472. Its totient is φ = 349920.

The previous prime is 626393. The next prime is 626443. The reversal of 626409 is 904626.

It is not a de Polignac number, because 626409 - 2⁴ = 626393 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a Curzon number.

626409 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (626489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3762 + ... + 3924.

2⁶²⁶⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

626409 is a deficient number, since it is larger than the sum of its proper divisors (431063).

626409 is a wasteful number, since it uses less digits than its factorization.

626409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 626409 is about 791.4600432113. The cubic root of 626409 is about 85.5629986091.

It can be divided in two parts, 626 and 409, that added together give a triangular number (1035 = T₄₅).

The spelling of 626409 in words is "six hundred twenty-six thousand, four hundred nine".