20216656 has 10 divisors (see below), whose sum is σ = 39169802. Its totient is φ = 10108320.

The previous prime is 20216641. The next prime is 20216659. The reversal of 20216656 is 65661202.

It can be written as a sum of positive squares in only one way, i.e., 19184400 + 1032256 = 4380^2 + 1016^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20216659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 631755 + ... + 631786.

Almost surely, 2^20216656 is an apocalyptic number.

It is an amenable number.

20216656 is a deficient number, since it is larger than the sum of its proper divisors (18953146).

20216656 is a wasteful number, since it uses less digits than its factorization.

20216656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1263549 (or 1263543 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 20216656 is about 4496.2935847206. The cubic root of 20216656 is about 272.4184016267.

Adding to 20216656 its reverse (65661202), we get a palindrome (85877858).

The spelling of 20216656 in words is "twenty million, two hundred sixteen thousand, six hundred fifty-six".