1680040891 has 2 divisors, whose sum is σ = 1680040892. Its totient is φ = 1680040890.

The previous prime is 1680040889. The next prime is 1680040903. The reversal of 1680040891 is 1980400861.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1980400861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1680040891 - 2¹ = 1680040889 is a prime.

Together with 1680040889, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1680040891.

It is not a weakly prime, because it can be changed into another prime (1680040391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 840020445 + 840020446.

It is an arithmetic number, because the mean of its divisors is an integer number (840020446).

Almost surely, 2^1680040891 is an apocalyptic number.

1680040891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1680040891 is an equidigital number, since it uses as much as digits as its factorization.

1680040891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 1680040891 is about 40988.3018799267. The cubic root of 1680040891 is about 1188.7940354312.

The spelling of 1680040891 in words is "one billion, six hundred eighty million, forty thousand, eight hundred ninety-one".