1813490566561 has 4 divisors (see below), whose sum is σ = 1813503366724. Its totient is φ = 1813477766400.

The previous prime is 1813490566541. The next prime is 1813490566567. The reversal of 1813490566561 is 1656650943181.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 538251126336 + 1275239440225 = 733656^2 + 1129265^2 .

It is a cyclic number.

It is not a de Polignac number, because 1813490566561 - 2¹⁷ = 1813490435489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1813490566567) 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 3 ways as a sum of consecutive naturals, for example, 6185160 + ... + 6471721.

It is an arithmetic number, because the mean of its divisors is an integer number (453375841681).

Almost surely, 2^{1813490566561} is an apocalyptic number.

It is an amenable number.

1813490566561 is a deficient number, since it is larger than the sum of its proper divisors (12800163).

1813490566561 is a wasteful number, since it uses less digits than its factorization.

1813490566561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12800162.

The product of its (nonzero) digits is 4665600, while the sum is 55.

The spelling of 1813490566561 in words is "one trillion, eight hundred thirteen billion, four hundred ninety million, five hundred sixty-six thousand, five hundred sixty-one".