20218819 has 2 divisors, whose sum is σ = 20218820. Its totient is φ = 20218818.

The previous prime is 20218799. The next prime is 20218837. The reversal of 20218819 is 91881202.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20218819 - 2⁵ = 20218787 is a prime.

It is a super-2 number, since 2×20218819² = 817601283509522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20218859) 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, 10109409 + 10109410.

It is an arithmetic number, because the mean of its divisors is an integer number (10109410).

Almost surely, 2^20218819 is an apocalyptic number.

20218819 is a deficient number, since it is larger than the sum of its proper divisors (1).

20218819 is an equidigital number, since it uses as much as digits as its factorization.

20218819 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 20218819 is about 4496.5341097339. The cubic root of 20218819 is about 272.4281167183.

The spelling of 20218819 in words is "twenty million, two hundred eighteen thousand, eight hundred nineteen".