1256550613 has 4 divisors (see below), whose sum is σ = 1259831808. Its totient is φ = 1253269420.

The previous prime is 1256550611. The next prime is 1256550637. The reversal of 1256550613 is 3160556521.

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.

It is a cyclic number.

It is not a de Polignac number, because 1256550613 - 2¹ = 1256550611 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256550611) 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, 1640023 + ... + 1640788.

It is an arithmetic number, because the mean of its divisors is an integer number (314957952).

Almost surely, 2^1256550613 is an apocalyptic number.

It is an amenable number.

1256550613 is a deficient number, since it is larger than the sum of its proper divisors (3281195).

1256550613 is an equidigital number, since it uses as much as digits as its factorization.

1256550613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3281194.

The product of its (nonzero) digits is 27000, while the sum is 34.

The square root of 1256550613 is about 35447.8576644626. The cubic root of 1256550613 is about 1079.0957832332.

The spelling of 1256550613 in words is "one billion, two hundred fifty-six million, five hundred fifty thousand, six hundred thirteen".