21012020201 has 4 divisors (see below), whose sum is σ = 21015333972. Its totient is φ = 21008706432.

The previous prime is 21012020149. The next prime is 21012020221. The reversal of 21012020201 is 10202021012.

It is a happy number.

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 11518440976 + 9493579225 = 107324^2 + 97435^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012020201 - 2³⁴ = 3832151017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012020221) 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, 1647356 + ... + 1660061.

It is an arithmetic number, because the mean of its divisors is an integer number (5253833493).

Almost surely, 2^21012020201 is an apocalyptic number.

It is an amenable number.

21012020201 is a deficient number, since it is larger than the sum of its proper divisors (3313771).

21012020201 is an equidigital number, since it uses as much as digits as its factorization.

21012020201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3313770.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21012020201 its reverse (10202021012), we get a palindrome (31214041213).

The spelling of 21012020201 in words is "twenty-one billion, twelve million, twenty thousand, two hundred one".