20993839 has 2 divisors, whose sum is σ = 20993840. Its totient is φ = 20993838.

The previous prime is 20993831. The next prime is 20993857. The reversal of 20993839 is 93839902.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20993839 - 2³ = 20993831 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20993795 and 20993804.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20993831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10496919 + 10496920.

It is an arithmetic number, because the mean of its divisors is an integer number (10496920).

Almost surely, 2^20993839 is an apocalyptic number.

20993839 is a deficient number, since it is larger than the sum of its proper divisors (1).

20993839 is an equidigital number, since it uses as much as digits as its factorization.

20993839 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 43.

The square root of 20993839 is about 4581.9034254336. The cubic root of 20993839 is about 275.8654344724.

The spelling of 20993839 in words is "twenty million, nine hundred ninety-three thousand, eight hundred thirty-nine".