1256138388256 has 12 divisors (see below), whose sum is σ = 2473022451942. Its totient is φ = 628069194112.

The previous prime is 1256138388209. The next prime is 1256138388257. The reversal of 1256138388256 is 6528838316521.

It can be written as a sum of positive squares in only one way, i.e., 749644272400 + 506494115856 = 865820^2 + 711684^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1256138388256.

It is not an unprimeable number, because it can be changed into a prime (1256138388257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19627162285 + ... + 19627162348.

Almost surely, 2^{1256138388256} is an apocalyptic number.

1256138388256 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1256138388256 is a deficient number, since it is larger than the sum of its proper divisors (1216884063686).

1256138388256 is an equidigital number, since it uses as much as digits as its factorization.

1256138388256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39254324643 (or 39254324635 counting only the distinct ones).

The product of its digits is 16588800, while the sum is 58.

The spelling of 1256138388256 in words is "one trillion, two hundred fifty-six billion, one hundred thirty-eight million, three hundred eighty-eight thousand, two hundred fifty-six".