1261346871409 has 9 divisors (see below), whose sum is σ = 1268004566721. Its totient is φ = 1254723968400.

The previous prime is 1261346871401. The next prime is 1261346871427. The reversal of 1261346871409 is 9041786431621.

The square root of 1261346871409 is 1123097.

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

It can be written as a sum of positive squares in 4 ways, for example, as 925030386225 + 336316485184 = 961785^2 + 579928^2 .

It is not a de Polignac number, because 1261346871409 - 2³ = 1261346871401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261346871401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 221247259 + ... + 221252959.

Almost surely, 2^{1261346871409} is an apocalyptic number.

1261346871409 is the 1123097-th square number.

1261346871409 is the 561549-th centered octagonal number.

It is an amenable number.

1261346871409 is a deficient number, since it is larger than the sum of its proper divisors (6657695312).

1261346871409 is an frugal number, since it uses more digits than its factorization.

1261346871409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11796 (or 5898 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 52.

The spelling of 1261346871409 in words is "one trillion, two hundred sixty-one billion, three hundred forty-six million, eight hundred seventy-one thousand, four hundred nine".