20110021 has 8 divisors (see below), whose sum is σ = 20917080. Its totient is φ = 19310592.

The previous prime is 20109989. The next prime is 20110043. The reversal of 20110021 is 12001102.

It can be written as a sum of positive squares in 4 ways, for example, as 617796 + 19492225 = 786^2 + 4415^2 .

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 20110021 - 2⁵ = 20109989 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20109986 and 20110013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20114021) 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, 3801 + ... + 7393.

It is an arithmetic number, because the mean of its divisors is an integer number (2614635).

Almost surely, 2^20110021 is an apocalyptic number.

It is an amenable number.

20110021 is a deficient number, since it is larger than the sum of its proper divisors (807059).

20110021 is a wasteful number, since it uses less digits than its factorization.

20110021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3815.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 20110021 is about 4484.4198063964. The cubic root of 20110021 is about 271.9385899786.

Adding to 20110021 its reverse (12001102), we get a palindrome (32111123).

The spelling of 20110021 in words is "twenty million, one hundred ten thousand, twenty-one".