1680549142681 has 4 divisors (see below), whose sum is σ = 1680555474612. Its totient is φ = 1680542810752.

The previous prime is 1680549142651. The next prime is 1680549142703. The reversal of 1680549142681 is 1862419450861.

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 870712934400 + 809836208281 = 933120^2 + 899909^2 .

It is a cyclic number.

It is not a de Polignac number, because 1680549142681 - 2¹⁵ = 1680549109913 is a prime.

It is a super-2 number, since 2×1680549142681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1680549142651) 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, 2749600 + ... + 3304753.

It is an arithmetic number, because the mean of its divisors is an integer number (420138868653).

Almost surely, 2^{1680549142681} is an apocalyptic number.

It is an amenable number.

1680549142681 is a deficient number, since it is larger than the sum of its proper divisors (6331931).

1680549142681 is an equidigital number, since it uses as much as digits as its factorization.

1680549142681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6331930.

The product of its (nonzero) digits is 3317760, while the sum is 55.

The spelling of 1680549142681 in words is "one trillion, six hundred eighty billion, five hundred forty-nine million, one hundred forty-two thousand, six hundred eighty-one".