1291666345225 has 9 divisors (see below), whose sum is σ = 1601673314503. Its totient is φ = 1033328530120.

The previous prime is 1291666345187. The next prime is 1291666345279. The reversal of 1291666345225 is 5225436661921.

The square root of 1291666345225 is 1136515.

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., 464999884281 + 826666460944 = 681909^2 + 909212^2 .

It is not a de Polignac number, because 1291666345225 - 2⁹ = 1291666344713 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 5568924 + ... + 5796226.

Almost surely, 2^{1291666345225} is an apocalyptic number.

1291666345225 is the 1136515-th square number.

1291666345225 is the 568258-th centered octagonal number.

It is an amenable number.

1291666345225 is a deficient number, since it is larger than the sum of its proper divisors (310006969278).

1291666345225 is an frugal number, since it uses more digits than its factorization.

1291666345225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 454616 (or 227308 counting only the distinct ones).

The product of its digits is 4665600, while the sum is 52.

The spelling of 1291666345225 in words is "one trillion, two hundred ninety-one billion, six hundred sixty-six million, three hundred forty-five thousand, two hundred twenty-five".