1205404172281 has 3 divisors (see below), whose sum is σ = 1205405270191. Its totient is φ = 1205403074372.

The previous prime is 1205404172279. The next prime is 1205404172309. The reversal of 1205404172281 is 1822714045021.

The square root of 1205404172281 is 1097909.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 236478936681 + 968925235600 = 486291^2 + 984340^2 .

It is not a de Polignac number, because 1205404172281 - 2¹ = 1205404172279 is a prime.

It is a super-2 number, since 2×1205404172281² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1205404172281.

It is not an unprimeable number, because it can be changed into a prime (1205404172381) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 548955 + ... + 1646863.

Almost surely, 2^{1205404172281} is an apocalyptic number.

1205404172281 is the 1097909-th square number.

1205404172281 is the 548955-th centered octagonal number.

It is an amenable number.

1205404172281 is a deficient number, since it is larger than the sum of its proper divisors (1097910).

1205404172281 is an frugal number, since it uses more digits than its factorization.

1205404172281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2195818 (or 1097909 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 37.

The spelling of 1205404172281 in words is "one trillion, two hundred five billion, four hundred four million, one hundred seventy-two thousand, two hundred eighty-one".