20218843 has 2 divisors, whose sum is σ = 20218844. Its totient is φ = 20218842.

The previous prime is 20218837. The next prime is 20218859. The reversal of 20218843 is 34881202.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20218843 is a prime.

It is a super-2 number, since 2×20218843² = 817603224517298, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20218343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10109421 + 10109422.

It is an arithmetic number, because the mean of its divisors is an integer number (10109422).

Almost surely, 2^20218843 is an apocalyptic number.

20218843 is the 2404-th centered heptagonal number.

20218843 is a deficient number, since it is larger than the sum of its proper divisors (1).

20218843 is an equidigital number, since it uses as much as digits as its factorization.

20218843 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 20218843 is about 4496.5367784552. The cubic root of 20218843 is about 272.4282245101.

The spelling of 20218843 in words is "twenty million, two hundred eighteen thousand, eight hundred forty-three".