20217231 has 6 divisors (see below), whose sum is σ = 29202680. Its totient is φ = 13478148.

The previous prime is 20217229. The next prime is 20217259. The reversal of 20217231 is 13271202.

It is not a de Polignac number, because 20217231 - 2¹ = 20217229 is a prime.

It is a super-2 number, since 2×20217231² = 817472858614722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20217931) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1123171 + ... + 1123188.

Almost surely, 2^20217231 is an apocalyptic number.

20217231 is a deficient number, since it is larger than the sum of its proper divisors (8985449).

20217231 is a wasteful number, since it uses less digits than its factorization.

20217231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2246365 (or 2246362 counting only the distinct ones).

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

The square root of 20217231 is about 4496.3575258202. The cubic root of 20217231 is about 272.4209843008.

Adding to 20217231 its reverse (13271202), we get a palindrome (33488433).

The spelling of 20217231 in words is "twenty million, two hundred seventeen thousand, two hundred thirty-one".