20818739 has 2 divisors, whose sum is σ = 20818740. Its totient is φ = 20818738.

The previous prime is 20818649. The next prime is 20818741. The reversal of 20818739 is 93781802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20818739 - 2¹⁶ = 20753203 is a prime.

Together with 20818741, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20818789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10409369 + 10409370.

It is an arithmetic number, because the mean of its divisors is an integer number (10409370).

Almost surely, 2^20818739 is an apocalyptic number.

20818739 is a deficient number, since it is larger than the sum of its proper divisors (1).

20818739 is an equidigital number, since it uses as much as digits as its factorization.

20818739 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 20818739 is about 4562.7556366740. The cubic root of 20818739 is about 275.0963364959.

The spelling of 20818739 in words is "twenty million, eight hundred eighteen thousand, seven hundred thirty-nine".