20309903 has 2 divisors, whose sum is σ = 20309904. Its totient is φ = 20309902.

The previous prime is 20309893. The next prime is 20309921. The reversal of 20309903 is 30990302.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20309903 - 2¹⁰ = 20308879 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20309923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10154951 + 10154952.

It is an arithmetic number, because the mean of its divisors is an integer number (10154952).

Almost surely, 2^20309903 is an apocalyptic number.

20309903 is a deficient number, since it is larger than the sum of its proper divisors (1).

20309903 is an equidigital number, since it uses as much as digits as its factorization.

20309903 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1458, while the sum is 26.

The square root of 20309903 is about 4506.6509738386. The cubic root of 20309903 is about 272.8365921781.

It can be divided in two parts, 20309 and 903, that added together give a palindrome (21212).

The spelling of 20309903 in words is "twenty million, three hundred nine thousand, nine hundred three".