1256724224257 has 4 divisors (see below), whose sum is σ = 1256743012420. Its totient is φ = 1256705436096.

The previous prime is 1256724224221. The next prime is 1256724224269. The reversal of 1256724224257 is 7524224276521.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 318817200321 + 937907023936 = 564639^2 + 968456^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1256724224257 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1256724224257.

It is not an unprimeable number, because it can be changed into a prime (1256724224297) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9293388 + ... + 9427645.

It is an arithmetic number, because the mean of its divisors is an integer number (314185753105).

Almost surely, 2^{1256724224257} is an apocalyptic number.

It is an amenable number.

1256724224257 is a deficient number, since it is larger than the sum of its proper divisors (18788163).

1256724224257 is an equidigital number, since it uses as much as digits as its factorization.

1256724224257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18788162.

The product of its digits is 3763200, while the sum is 49.

The spelling of 1256724224257 in words is "one trillion, two hundred fifty-six billion, seven hundred twenty-four million, two hundred twenty-four thousand, two hundred fifty-seven".