1680611821 has 16 divisors (see below), whose sum is σ = 1976358528. Its totient is φ = 1399320000.

The previous prime is 1680611809. The next prime is 1680611827. The reversal of 1680611821 is 1281160861.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1680611821 - 2¹⁷ = 1680480749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1680611827) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15046 + ... + 59896.

It is an arithmetic number, because the mean of its divisors is an integer number (123522408).

Almost surely, 2^1680611821 is an apocalyptic number.

It is an amenable number.

1680611821 is a deficient number, since it is larger than the sum of its proper divisors (295746707).

1680611821 is a wasteful number, since it uses less digits than its factorization.

1680611821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45012.

The product of its (nonzero) digits is 4608, while the sum is 34.

The square root of 1680611821 is about 40995.2658364353. The cubic root of 1680611821 is about 1188.9286832075.

The spelling of 1680611821 in words is "one billion, six hundred eighty million, six hundred eleven thousand, eight hundred twenty-one".