1256820 has 24 divisors (see below), whose sum is σ = 3519264. Its totient is φ = 335136.

The previous prime is 1256819. The next prime is 1256821. The reversal of 1256820 is 286521.

It is an interprime number because it is at equal distance from previous prime (1256819) and next prime (1256821).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256821) 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 7 ways as a sum of consecutive naturals, for example, 10414 + ... + 10533.

It is an arithmetic number, because the mean of its divisors is an integer number (146636).

2^1256820 is an apocalyptic number.

1256820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1256820 is an abundant number, since it is smaller than the sum of its proper divisors (2262444).

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

1256820 is a wasteful number, since it uses less digits than its factorization.

1256820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20959 (or 20957 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 1256820 is about 1121.0798365861. The cubic root of 1256820 is about 107.9172892106.

Subtracting from 1256820 its reverse (286521), we obtain a cube (970299 = 99³).

The spelling of 1256820 in words is "one million, two hundred fifty-six thousand, eight hundred twenty".