20211005 has 8 divisors (see below), whose sum is σ = 24320472. Its totient is φ = 16123968.

The previous prime is 20211001. The next prime is 20211007. The reversal of 20211005 is 50011202.

It can be written as a sum of positive squares in 4 ways, for example, as 727609 + 19483396 = 853^2 + 4414^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20211005 - 2² = 20211001 is a prime.

It is a super-2 number, since 2×20211005² = 816969446220050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211001) 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 7 ways as a sum of consecutive naturals, for example, 3554 + ... + 7283.

It is an arithmetic number, because the mean of its divisors is an integer number (3040059).

Almost surely, 2^20211005 is an apocalyptic number.

It is an amenable number.

20211005 is a deficient number, since it is larger than the sum of its proper divisors (4109467).

20211005 is a wasteful number, since it uses less digits than its factorization.

20211005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11215.

The product of its (nonzero) digits is 20, while the sum is 11.

The square root of 20211005 is about 4495.6651343266. The cubic root of 20211005 is about 272.3930169498.

Adding to 20211005 its reverse (50011202), we get a palindrome (70222207).

The spelling of 20211005 in words is "twenty million, two hundred eleven thousand, five".