1256205517423 has 2 divisors, whose sum is σ = 1256205517424. Its totient is φ = 1256205517422.

The previous prime is 1256205517421. The next prime is 1256205517487. The reversal of 1256205517423 is 3247155026521.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1256205517423 - 2¹ = 1256205517421 is a prime.

Together with 1256205517421, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1256205517423.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1256205517421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 628102758711 + 628102758712.

It is an arithmetic number, because the mean of its divisors is an integer number (628102758712).

Almost surely, 2^{1256205517423} is an apocalyptic number.

1256205517423 is a deficient number, since it is larger than the sum of its proper divisors (1).

1256205517423 is an equidigital number, since it uses as much as digits as its factorization.

1256205517423 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504000, while the sum is 43.

The spelling of 1256205517423 in words is "one trillion, two hundred fifty-six billion, two hundred five million, five hundred seventeen thousand, four hundred twenty-three".