21450520230121 has 4 divisors (see below), whose sum is σ = 21559406119812. Its totient is φ = 21341634340432.

The previous prime is 21450520230089. The next prime is 21450520230131. The reversal of 21450520230121 is 12103202505412.

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 12466802858896 + 8983717371225 = 3530836^2 + 2997285^2 .

It is a cyclic number.

It is not a de Polignac number, because 21450520230121 - 2⁵ = 21450520230089 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 21450520230121.

It is not an unprimeable number, because it can be changed into a prime (21450520230131) 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, 54442944550 + ... + 54442944943.

It is an arithmetic number, because the mean of its divisors is an integer number (5389851529953).

Almost surely, 2^{21450520230121} is an apocalyptic number.

It is an amenable number.

21450520230121 is a deficient number, since it is larger than the sum of its proper divisors (108885889691).

21450520230121 is a wasteful number, since it uses less digits than its factorization.

21450520230121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108885889690.

The product of its (nonzero) digits is 4800, while the sum is 28.

Adding to 21450520230121 its reverse (12103202505412), we get a palindrome (33553722735533).

The spelling of 21450520230121 in words is "twenty-one trillion, four hundred fifty billion, five hundred twenty million, two hundred thirty thousand, one hundred twenty-one".