21020121020201 has 4 divisors (see below), whose sum is σ = 21228241030404. Its totient is φ = 20812001010000.

The previous prime is 21020121020191. The next prime is 21020121020231. The reversal of 21020121020201 is 10202012102012.

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 20631798866176 + 388322154025 = 4542224^2 + 623155^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020121020201 - 2⁶ = 21020121020137 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020121020231) 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, 104060004950 + ... + 104060005151.

It is an arithmetic number, because the mean of its divisors is an integer number (5307060257601).

Almost surely, 2^{21020121020201} is an apocalyptic number.

It is an amenable number.

21020121020201 is a deficient number, since it is larger than the sum of its proper divisors (208120010203).

21020121020201 is a wasteful number, since it uses less digits than its factorization.

21020121020201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208120010202.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21020121020201 its reverse (10202012102012), we get a palindrome (31222133122213).

It can be divided in two parts, 2102012 and 1020201, that multiplied together give a palindrome (2144474744412).

The spelling of 21020121020201 in words is "twenty-one trillion, twenty billion, one hundred twenty-one million, twenty thousand, two hundred one".