21301365121 has 4 divisors (see below), whose sum is σ = 21302009044. Its totient is φ = 21300721200.

The previous prime is 21301365119. The next prime is 21301365149. The reversal of 21301365121 is 12156310312.

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 15304411521 + 5996953600 = 123711^2 + 77440^2 .

It is a cyclic number.

It is not a de Polignac number, because 21301365121 - 2¹ = 21301365119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21301365181) 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, 269490 + ... + 339451.

It is an arithmetic number, because the mean of its divisors is an integer number (5325502261).

Almost surely, 2^21301365121 is an apocalyptic number.

It is an amenable number.

21301365121 is a deficient number, since it is larger than the sum of its proper divisors (643923).

21301365121 is an equidigital number, since it uses as much as digits as its factorization.

21301365121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643922.

The product of its (nonzero) digits is 1080, while the sum is 25.

Adding to 21301365121 its reverse (12156310312), we get a palindrome (33457675433).

The spelling of 21301365121 in words is "twenty-one billion, three hundred one million, three hundred sixty-five thousand, one hundred twenty-one".