20021843 has 2 divisors, whose sum is σ = 20021844. Its totient is φ = 20021842.

The previous prime is 20021831. The next prime is 20021849. The reversal of 20021843 is 34812002.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20021843 - 2¹⁴ = 20005459 is a prime.

It is not a weakly prime, because it can be changed into another prime (20021849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010921 + 10010922.

It is an arithmetic number, because the mean of its divisors is an integer number (10010922).

Almost surely, 2^20021843 is an apocalyptic number.

20021843 is a deficient number, since it is larger than the sum of its proper divisors (1).

20021843 is an equidigital number, since it uses as much as digits as its factorization.

20021843 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 20021843 is about 4474.5774102143. The cubic root of 20021843 is about 271.5405440798.

Adding to 20021843 its reverse (34812002), we get a palindrome (54833845).

It can be divided in two parts, 2002 and 1843, that multiplied together give a triangular number (3689686 = T₂₇₁₆).

The spelling of 20021843 in words is "twenty million, twenty-one thousand, eight hundred forty-three".