1256513 has 4 divisors (see below), whose sum is σ = 1311168. Its totient is φ = 1201860.

The previous prime is 1256477. The next prime is 1256531. The reversal of 1256513 is 3156521.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3156521 = 53 ⋅59557.

It is a cyclic number.

It is not a de Polignac number, because 1256513 - 2⁶ = 1256449 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 54631 = 1256513 / (1 + 2 + 5 + 6 + 5 + 1 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256533) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27293 + ... + 27338.

It is an arithmetic number, because the mean of its divisors is an integer number (327792).

2^1256513 is an apocalyptic number.

It is an amenable number.

1256513 is a deficient number, since it is larger than the sum of its proper divisors (54655).

1256513 is an equidigital number, since it uses as much as digits as its factorization.

1256513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54654.

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

The square root of 1256513 is about 1120.9429066638. The cubic root of 1256513 is about 107.9085016076.

The spelling of 1256513 in words is "one million, two hundred fifty-six thousand, five hundred thirteen".