1256531 has 2 divisors, whose sum is σ = 1256532. Its totient is φ = 1256530.

The previous prime is 1256477. The next prime is 1256533. The reversal of 1256531 is 1356521.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1256531 is a prime.

It is a super-2 number, since 2×1256531² = 3157740307922, which contains 22 as substring.

Together with 1256533, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 1256497 and 1256506.

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

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628265 + 628266.

It is an arithmetic number, because the mean of its divisors is an integer number (628266).

2^1256531 is an apocalyptic number.

1256531 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256531 is an equidigital number, since it uses as much as digits as its factorization.

1256531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 900, while the sum is 23.

The square root of 1256531 is about 1120.9509355900. The cubic root of 1256531 is about 107.9090168811.

The spelling of 1256531 in words is "one million, two hundred fifty-six thousand, five hundred thirty-one".