20843239 has 2 divisors, whose sum is σ = 20843240. Its totient is φ = 20843238.

The previous prime is 20843237. The next prime is 20843287. The reversal of 20843239 is 93234802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20843239 - 2¹ = 20843237 is a prime.

It is a super-2 number, since 2×20843239² = 868881224022242, which contains 22 as substring.

Together with 20843237, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20843239.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20843237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10421619 + 10421620.

It is an arithmetic number, because the mean of its divisors is an integer number (10421620).

Almost surely, 2^20843239 is an apocalyptic number.

20843239 is a deficient number, since it is larger than the sum of its proper divisors (1).

20843239 is an equidigital number, since it uses as much as digits as its factorization.

20843239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 20843239 is about 4565.4396283381. The cubic root of 20843239 is about 275.2042075521.

The spelling of 20843239 in words is "twenty million, eight hundred forty-three thousand, two hundred thirty-nine".