1256851 has 4 divisors (see below), whose sum is σ = 1259104. Its totient is φ = 1254600.

The previous prime is 1256837. The next prime is 1256863. The reversal of 1256851 is 1586521.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1586521 = 1201 ⋅1321.

It is a cyclic number.

It is not a de Polignac number, because 1256851 - 2⁵ = 1256819 is a prime.

It is a Duffinian number.

1256851 is a lucky 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 3 ways as a sum of consecutive naturals, for example, 406 + ... + 1636.

It is an arithmetic number, because the mean of its divisors is an integer number (314776).

2^1256851 is an apocalyptic number.

1256851 is a deficient number, since it is larger than the sum of its proper divisors (2253).

1256851 is a wasteful number, since it uses less digits than its factorization.

1256851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2252.

The product of its digits is 2400, while the sum is 28.

The square root of 1256851 is about 1121.0936624564. The cubic root of 1256851 is about 107.9181764786.

The spelling of 1256851 in words is "one million, two hundred fifty-six thousand, eight hundred fifty-one".