20215206 has 72 divisors (see below), whose sum is σ = 50207976. Its totient is φ = 5829120.

The previous prime is 20215171. The next prime is 20215211. The reversal of 20215206 is 60251202.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 104646 + ... + 104838.

It is an arithmetic number, because the mean of its divisors is an integer number (697333).

Almost surely, 2^20215206 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20215206, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25103988).

20215206 is an abundant number, since it is smaller than the sum of its proper divisors (29992770).

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

20215206 is a wasteful number, since it uses less digits than its factorization.

20215206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258 (or 232 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 20215206 is about 4496.1323379100. The cubic root of 20215206 is about 272.4118885792.

Adding to 20215206 its reverse (60251202), we get a palindrome (80466408).

It can be divided in two parts, 2021 and 5206, that added together give a palindrome (7227).

The spelling of 20215206 in words is "twenty million, two hundred fifteen thousand, two hundred six".