21012320201 has 4 divisors (see below), whose sum is σ = 21064720404. Its totient is φ = 20959920000.

The previous prime is 21012320179. The next prime is 21012320207. The reversal of 21012320201 is 10202321012.

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 13325239225 + 7687080976 = 115435^2 + 87676^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012320201 - 2²⁶ = 20945211337 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21012320207) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26199500 + ... + 26200301.

It is an arithmetic number, because the mean of its divisors is an integer number (5266180101).

Almost surely, 2^21012320201 is an apocalyptic number.

It is an amenable number.

21012320201 is a deficient number, since it is larger than the sum of its proper divisors (52400203).

21012320201 is an equidigital number, since it uses as much as digits as its factorization.

21012320201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52400202.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21012320201 its reverse (10202321012), we get a palindrome (31214641213).

The spelling of 21012320201 in words is "twenty-one billion, twelve million, three hundred twenty thousand, two hundred one".