20217123 has 12 divisors (see below), whose sum is σ = 29273400. Its totient is φ = 13445376.

The previous prime is 20217103. The next prime is 20217137. The reversal of 20217123 is 32171202.

It is not a de Polignac number, because 20217123 - 2¹⁰ = 20216099 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20217096 and 20217105.

It is not an unprimeable number, because it can be changed into a prime (20217103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1540 + ... + 6542.

It is an arithmetic number, because the mean of its divisors is an integer number (2439450).

Almost surely, 2^20217123 is an apocalyptic number.

20217123 is a deficient number, since it is larger than the sum of its proper divisors (9056277).

20217123 is a wasteful number, since it uses less digits than its factorization.

20217123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5458 (or 5455 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 20217123 is about 4496.3455160830. The cubic root of 20217123 is about 272.4204992109.

Adding to 20217123 its reverse (32171202), we get a palindrome (52388325).

The spelling of 20217123 in words is "twenty million, two hundred seventeen thousand, one hundred twenty-three".