20421321101 has 4 divisors (see below), whose sum is σ = 20422007772. Its totient is φ = 20420634432.

The previous prime is 20421321091. The next prime is 20421321127. The reversal of 20421321101 is 10112312402.

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 1411805476 + 19009515625 = 37574^2 + 137875^2 .

It is a cyclic number.

It is not a de Polignac number, because 20421321101 - 2²⁶ = 20354212237 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20421321101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421321161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 296606 + ... + 358911.

It is an arithmetic number, because the mean of its divisors is an integer number (5105501943).

Almost surely, 2^20421321101 is an apocalyptic number.

It is an amenable number.

20421321101 is a deficient number, since it is larger than the sum of its proper divisors (686671).

20421321101 is an equidigital number, since it uses as much as digits as its factorization.

20421321101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 686670.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 20421321101 its reverse (10112312402), we get a palindrome (30533633503).

The spelling of 20421321101 in words is "twenty billion, four hundred twenty-one million, three hundred twenty-one thousand, one hundred one".