20839997 has 2 divisors, whose sum is σ = 20839998. Its totient is φ = 20839996.

The previous prime is 20839969. The next prime is 20839999. The reversal of 20839997 is 79993802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12013156 + 8826841 = 3466^2 + 2971^2 .

It is a cyclic number.

It is not a de Polignac number, because 20839997 - 2⁶ = 20839933 is a prime.

Together with 20839999, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20839999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10419998 + 10419999.

It is an arithmetic number, because the mean of its divisors is an integer number (10419999).

Almost surely, 2^20839997 is an apocalyptic number.

It is an amenable number.

20839997 is a deficient number, since it is larger than the sum of its proper divisors (1).

20839997 is an equidigital number, since it uses as much as digits as its factorization.

20839997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 20839997 is about 4565.0845556244. The cubic root of 20839997 is about 275.1899382039.

The spelling of 20839997 in words is "twenty million, eight hundred thirty-nine thousand, nine hundred ninety-seven".