1660200220561 has 4 divisors (see below), whose sum is σ = 1660205964852. Its totient is φ = 1660194476272.

The previous prime is 1660200220559. The next prime is 1660200220573. The reversal of 1660200220561 is 1650220020661.

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 665505166225 + 994695054336 = 815785^2 + 997344^2 .

It is a cyclic number.

It is not a de Polignac number, because 1660200220561 - 2¹ = 1660200220559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1660200220361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2414290 + ... + 3024763.

It is an arithmetic number, because the mean of its divisors is an integer number (415051491213).

Almost surely, 2^{1660200220561} is an apocalyptic number.

It is an amenable number.

1660200220561 is a deficient number, since it is larger than the sum of its proper divisors (5744291).

1660200220561 is an equidigital number, since it uses as much as digits as its factorization.

1660200220561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5744290.

The product of its (nonzero) digits is 8640, while the sum is 31.

The spelling of 1660200220561 in words is "one trillion, six hundred sixty billion, two hundred million, two hundred twenty thousand, five hundred sixty-one".