1256543 has 2 divisors, whose sum is σ = 1256544. Its totient is φ = 1256542.

The previous prime is 1256533. The next prime is 1256573. The reversal of 1256543 is 3456521.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1256543 - 2¹⁰ = 1255519 is a prime.

It is a Sophie Germain prime.

It is an alternating number because its digits alternate between odd and even.

It is equal to p₉₆₉₂₀ and since 1256543 and 96920 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1256533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628271 + 628272.

It is an arithmetic number, because the mean of its divisors is an integer number (628272).

2^1256543 is an apocalyptic number.

1256543 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256543 is an equidigital number, since it uses as much as digits as its factorization.

1256543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3600, while the sum is 26.

The square root of 1256543 is about 1120.9562881754. The cubic root of 1256543 is about 107.9093603941.

The spelling of 1256543 in words is "one million, two hundred fifty-six thousand, five hundred forty-three".