21271206 has 32 divisors (see below), whose sum is σ = 46884096. Its totient is φ = 6380000.

The previous prime is 21271183. The next prime is 21271207. The reversal of 21271206 is 60217212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21271207) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5071 + ... + 8261.

It is an arithmetic number, because the mean of its divisors is an integer number (1465128).

Almost surely, 2^21271206 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21271206, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23442048).

21271206 is an abundant number, since it is smaller than the sum of its proper divisors (25612890).

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

21271206 is a wasteful number, since it uses less digits than its factorization.

21271206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3308.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 21271206 is about 4612.0717687391. The cubic root of 21271206 is about 277.0750186712.

Adding to 21271206 its reverse (60217212), we get a palindrome (81488418).

It can be divided in two parts, 2127 and 1206, that added together give a palindrome (3333).

The spelling of 21271206 in words is "twenty-one million, two hundred seventy-one thousand, two hundred six".