1245145771321 has 9 divisors (see below), whose sum is σ = 1253725948461. Its totient is φ = 1236623940864.

The previous prime is 1245145771273. The next prime is 1245145771327. The reversal of 1245145771321 is 1231775415421.

The square root of 1245145771321 is 1115861.

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 219341418921 + 1025804352400 = 468339^2 + 1012820^2 .

It is not a de Polignac number, because 1245145771321 - 2²⁷ = 1245011553593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1245145771327) 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, 166259545 + ... + 166267033.

Almost surely, 2^{1245145771321} is an apocalyptic number.

1245145771321 is the 1115861-st square number.

1245145771321 is the 557931-st centered octagonal number.

It is an amenable number.

1245145771321 is a deficient number, since it is larger than the sum of its proper divisors (8580177140).

1245145771321 is an frugal number, since it uses more digits than its factorization.

1245145771321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15276 (or 7638 counting only the distinct ones).

The product of its digits is 235200, while the sum is 43.

The spelling of 1245145771321 in words is "one trillion, two hundred forty-five billion, one hundred forty-five million, seven hundred seventy-one thousand, three hundred twenty-one".