20717216 has 24 divisors (see below), whose sum is σ = 43925364. Its totient is φ = 9561600.

The previous prime is 20717209. The next prime is 20717219. The reversal of 20717216 is 61271702.

It can be written as a sum of positive squares in 2 ways, for example, as 19324816 + 1392400 = 4396^2 + 1180^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is not an unprimeable number, because it can be changed into a prime (20717219) 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 in 3 ways as a sum of consecutive naturals, for example, 24485 + ... + 25316.

Almost surely, 2^20717216 is an apocalyptic number.

20717216 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

20717216 is an abundant number, since it is smaller than the sum of its proper divisors (23208148).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20717216 is a wasteful number, since it uses less digits than its factorization.

20717216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49824 (or 49816 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 26.

The square root of 20717216 is about 4551.6168555800. The cubic root of 20717216 is about 274.6484366992.

Adding to 20717216 its reverse (61271702), we get a palindrome (81988918).

The spelling of 20717216 in words is "twenty million, seven hundred seventeen thousand, two hundred sixteen".