20993239 has 2 divisors, whose sum is σ = 20993240. Its totient is φ = 20993238.

The previous prime is 20993237. The next prime is 20993257. The reversal of 20993239 is 93239902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20993239 - 2¹ = 20993237 is a prime.

It is a super-2 number, since 2×20993239² = 881432167422242, which contains 22 as substring.

Together with 20993237, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20993198 and 20993207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20993237) 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, 10496619 + 10496620.

It is an arithmetic number, because the mean of its divisors is an integer number (10496620).

Almost surely, 2^20993239 is an apocalyptic number.

20993239 is a deficient number, since it is larger than the sum of its proper divisors (1).

20993239 is an equidigital number, since it uses as much as digits as its factorization.

20993239 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26244, while the sum is 37.

The square root of 20993239 is about 4581.8379499934. The cubic root of 20993239 is about 275.8628063865.

The spelling of 20993239 in words is "twenty million, nine hundred ninety-three thousand, two hundred thirty-nine".