2078209891 has 2 divisors, whose sum is σ = 2078209892. Its totient is φ = 2078209890.

The previous prime is 2078209883. The next prime is 2078209901. The reversal of 2078209891 is 1989028702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2078209891 - 2³ = 2078209883 is a prime.

It is not a weakly prime, because it can be changed into another prime (2078209801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1039104945 + 1039104946.

It is an arithmetic number, because the mean of its divisors is an integer number (1039104946).

Almost surely, 2^2078209891 is an apocalyptic number.

2078209891 is a deficient number, since it is larger than the sum of its proper divisors (1).

2078209891 is an equidigital number, since it uses as much as digits as its factorization.

2078209891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 145152, while the sum is 46.

The square root of 2078209891 is about 45587.3874114321. The cubic root of 2078209891 is about 1276.1345566429.

The spelling of 2078209891 in words is "two billion, seventy-eight million, two hundred nine thousand, eight hundred ninety-one".