20906503 has 2 divisors, whose sum is σ = 20906504. Its totient is φ = 20906502.

The previous prime is 20906491. The next prime is 20906521. The reversal of 20906503 is 30560902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20906503 - 2⁹ = 20905991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20906533) 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, 10453251 + 10453252.

It is an arithmetic number, because the mean of its divisors is an integer number (10453252).

Almost surely, 2^20906503 is an apocalyptic number.

20906503 is a deficient number, since it is larger than the sum of its proper divisors (1).

20906503 is an equidigital number, since it uses as much as digits as its factorization.

20906503 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 20906503 is about 4572.3629558468. The cubic root of 20906503 is about 275.4823622359.

The spelling of 20906503 in words is "twenty million, nine hundred six thousand, five hundred three".