1261333394281 has 9 divisors (see below), whose sum is σ = 1275766017591. Its totient is φ = 1247062276944.

The previous prime is 1261333394249. The next prime is 1261333394287. The reversal of 1261333394281 is 1824933331621.

The square root of 1261333394281 is 1123091.

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., 242202763881 + 1019130630400 = 492141^2 + 1009520^2 .

It is not a de Polignac number, because 1261333394281 - 2⁵ = 1261333394249 is a prime.

It is a super-2 number, since 2×1261333394281² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261333394287) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 99948790 + ... + 99961408.

Almost surely, 2^{1261333394281} is an apocalyptic number.

1261333394281 is the 1123091-st square number.

1261333394281 is the 561546-th centered octagonal number.

It is an amenable number.

1261333394281 is a deficient number, since it is larger than the sum of its proper divisors (14432623310).

1261333394281 is an frugal number, since it uses more digits than its factorization.

1261333394281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25416 (or 12708 counting only the distinct ones).

The product of its digits is 559872, while the sum is 46.

The spelling of 1261333394281 in words is "one trillion, two hundred sixty-one billion, three hundred thirty-three million, three hundred ninety-four thousand, two hundred eighty-one".