20216021 has 16 divisors (see below), whose sum is σ = 23654400. Its totient is φ = 16921008.

The previous prime is 20216017. The next prime is 20216033. The reversal of 20216021 is 12061202.

It is a cyclic number.

It is not a de Polignac number, because 20216021 - 2² = 20216017 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20215987 and 20216005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20216221) 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 15 ways as a sum of consecutive naturals, for example, 76736 + ... + 76998.

It is an arithmetic number, because the mean of its divisors is an integer number (1478400).

Almost surely, 2^20216021 is an apocalyptic number.

It is an amenable number.

20216021 is a deficient number, since it is larger than the sum of its proper divisors (3438379).

20216021 is a wasteful number, since it uses less digits than its factorization.

20216021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 488.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 20216021 is about 4496.2229704498. Note that the first 3 decimals coincide. The cubic root of 20216021 is about 272.4155493994.

Adding to 20216021 its reverse (12061202), we get a palindrome (32277223).

The spelling of 20216021 in words is "twenty million, two hundred sixteen thousand, twenty-one".