1680206161 has 4 divisors (see below), whose sum is σ = 1697527972. Its totient is φ = 1662884352.

The previous prime is 1680206141. The next prime is 1680206183. The reversal of 1680206161 is 1616020861.

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 236206161 + 1444000000 = 15369^2 + 38000^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1680206161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1680206141) 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, 8660760 + ... + 8660953.

It is an arithmetic number, because the mean of its divisors is an integer number (424381993).

Almost surely, 2^1680206161 is an apocalyptic number.

It is an amenable number.

1680206161 is a deficient number, since it is larger than the sum of its proper divisors (17321811).

1680206161 is an equidigital number, since it uses as much as digits as its factorization.

1680206161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17321810.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 1680206161 is about 40990.3178933757. The cubic root of 1680206161 is about 1188.8330157420.

The spelling of 1680206161 in words is "one billion, six hundred eighty million, two hundred six thousand, one hundred sixty-one".