20778019 has 2 divisors, whose sum is σ = 20778020. Its totient is φ = 20778018.

The previous prime is 20778011. The next prime is 20778071. The reversal of 20778019 is 91087702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20778019 - 2³ = 20778011 is a prime.

It is a super-2 number, since 2×20778019² = 863452147128722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20778011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10389009 + 10389010.

It is an arithmetic number, because the mean of its divisors is an integer number (10389010).

Almost surely, 2^20778019 is an apocalyptic number.

20778019 is a deficient number, since it is larger than the sum of its proper divisors (1).

20778019 is an equidigital number, since it uses as much as digits as its factorization.

20778019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 20778019 is about 4558.2912368562. The cubic root of 20778019 is about 274.9168630231.

The spelling of 20778019 in words is "twenty million, seven hundred seventy-eight thousand, nineteen".