20071221 has 8 divisors (see below), whose sum is σ = 26810784. Its totient is φ = 13356240.

The previous prime is 20071217. The next prime is 20071267. The reversal of 20071221 is 12217002.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20071221 - 2² = 20071217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20071221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20071211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4146 + ... + 7571.

It is an arithmetic number, because the mean of its divisors is an integer number (3351348).

Almost surely, 2^20071221 is an apocalyptic number.

It is an amenable number.

20071221 is a deficient number, since it is larger than the sum of its proper divisors (6739563).

20071221 is a wasteful number, since it uses less digits than its factorization.

20071221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12291.

The product of its (nonzero) digits is 56, while the sum is 15.

The square root of 20071221 is about 4480.0916285273. The cubic root of 20071221 is about 271.7635858457.

Adding to 20071221 its reverse (12217002), we get a palindrome (32288223).

The spelling of 20071221 in words is "twenty million, seventy-one thousand, two hundred twenty-one".