20216506 has 4 divisors (see below), whose sum is σ = 30324762. Its totient is φ = 10108252.

The previous prime is 20216501. The next prime is 20216507. The reversal of 20216506 is 60561202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12145225 + 8071281 = 3485^2 + 2841^2 .

It is a super-2 number, since 2×20216506² = 817414229696072, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (20216501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5054125 + ... + 5054128.

Almost surely, 2^20216506 is an apocalyptic number.

20216506 is a deficient number, since it is larger than the sum of its proper divisors (10108256).

20216506 is a wasteful number, since it uses less digits than its factorization.

20216506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10108255.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 20216506 is about 4496.2769042843. The cubic root of 20216506 is about 272.4177278776.

Adding to 20216506 its reverse (60561202), we get a palindrome (80777708).

The spelling of 20216506 in words is "twenty million, two hundred sixteen thousand, five hundred six".