1256605 has 24 divisors (see below), whose sum is σ = 1838592. Its totient is φ = 820512.

The previous prime is 1256597. The next prime is 1256611. The reversal of 1256605 is 5066521.

It is not a de Polignac number, because 1256605 - 2³ = 1256597 is a prime.

It is a super-2 number, since 2×1256605² = 3158112252050, which contains 22 as substring.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 1256605.

It is a congruent number.

It is an unprimeable number.

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, 5524 + ... + 5746.

It is an arithmetic number, because the mean of its divisors is an integer number (76608).

2^1256605 is an apocalyptic number.

It is an amenable number.

1256605 is a deficient number, since it is larger than the sum of its proper divisors (581987).

1256605 is a wasteful number, since it uses less digits than its factorization.

1256605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 265 (or 258 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 1256605 is about 1120.9839427931. The cubic root of 1256605 is about 107.9111351763.

The spelling of 1256605 in words is "one million, two hundred fifty-six thousand, six hundred five".