1256984049409 has 27 divisors (see below), whose sum is σ = 1390854629731. Its totient is φ = 1135144989440.

The previous prime is 1256984049367. The next prime is 1256984049457. The reversal of 1256984049409 is 9049404896521.

The square root of 1256984049409 is 1121153.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 768159343809 + 488824705600 = 876447^2 + 699160^2 .

It is not a de Polignac number, because 1256984049409 - 2²⁵ = 1256950494977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1256984049109) 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 26 ways as a sum of consecutive naturals, for example, 2799518817 + ... + 2799519265.

Almost surely, 2^{1256984049409} is an apocalyptic number.

1256984049409 is the 1121153-rd square number.

1256984049409 is the 560577-th centered octagonal number.

It is an amenable number.

1256984049409 is a deficient number, since it is larger than the sum of its proper divisors (133870580322).

1256984049409 is an frugal number, since it uses more digits than its factorization.

1256984049409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1374 (or 687 counting only the distinct ones).

The product of its (nonzero) digits is 22394880, while the sum is 61.

The spelling of 1256984049409 in words is "one trillion, two hundred fifty-six billion, nine hundred eighty-four million, forty-nine thousand, four hundred nine".