20101321021 has 4 divisors (see below), whose sum is σ = 20108799100. Its totient is φ = 20093842944.

The previous prime is 20101320977. The next prime is 20101321091. The reversal of 20101321021 is 12012310102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5185584121 + 14915736900 = 72011^2 + 122130^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101321021 - 2²³ = 20092932413 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20101320992 and 20101321010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20101321091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3735006 + ... + 3740383.

It is an arithmetic number, because the mean of its divisors is an integer number (5027199775).

Almost surely, 2^20101321021 is an apocalyptic number.

It is an amenable number.

20101321021 is a deficient number, since it is larger than the sum of its proper divisors (7478079).

20101321021 is an equidigital number, since it uses as much as digits as its factorization.

20101321021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7478078.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 20101321021 its reverse (12012310102), we get a palindrome (32113631123).

The spelling of 20101321021 in words is "twenty billion, one hundred one million, three hundred twenty-one thousand, twenty-one".