1721530666123 has 4 divisors (see below), whose sum is σ = 1730450514328. Its totient is φ = 1712610817920.

The previous prime is 1721530666103. The next prime is 1721530666133. The reversal of 1721530666123 is 3216660351271.

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

It is a cyclic number.

It is not a de Polignac number, because 1721530666123 - 2¹⁷ = 1721530535051 is a prime.

It is a super-2 number, since 2×1721530666123² (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 1721530666123.

It is not an unprimeable number, because it can be changed into a prime (1721530666103) 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, 4459923813 + ... + 4459924198.

It is an arithmetic number, because the mean of its divisors is an integer number (432612628582).

Almost surely, 2^{1721530666123} is an apocalyptic number.

1721530666123 is a deficient number, since it is larger than the sum of its proper divisors (8919848205).

1721530666123 is an equidigital number, since it uses as much as digits as its factorization.

1721530666123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8919848204.

The product of its (nonzero) digits is 272160, while the sum is 43.

The spelling of 1721530666123 in words is "one trillion, seven hundred twenty-one billion, five hundred thirty million, six hundred sixty-six thousand, one hundred twenty-three".