20621903 has 2 divisors, whose sum is σ = 20621904. Its totient is φ = 20621902.

The previous prime is 20621891. The next prime is 20621917. The reversal of 20621903 is 30912602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20621903 - 2¹⁰ = 20620879 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20621963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10310951 + 10310952.

It is an arithmetic number, because the mean of its divisors is an integer number (10310952).

Almost surely, 2^20621903 is an apocalyptic number.

20621903 is a deficient number, since it is larger than the sum of its proper divisors (1).

20621903 is an equidigital number, since it uses as much as digits as its factorization.

20621903 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 20621903 is about 4541.1345498675. The cubic root of 20621903 is about 274.2266005136.

The spelling of 20621903 in words is "twenty million, six hundred twenty-one thousand, nine hundred three".