21242511361 has 4 divisors (see below), whose sum is σ = 21272473300. Its totient is φ = 21212549424.

The previous prime is 21242511349. The next prime is 21242511413. The reversal of 21242511361 is 16311524212.

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 1352768400 + 19889742961 = 36780^2 + 141031^2 .

It is a cyclic number.

It is not a de Polignac number, because 21242511361 - 2³¹ = 19095027713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21242521361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14979906 + ... + 14981323.

It is an arithmetic number, because the mean of its divisors is an integer number (5318118325).

Almost surely, 2^21242511361 is an apocalyptic number.

It is an amenable number.

21242511361 is a deficient number, since it is larger than the sum of its proper divisors (29961939).

21242511361 is an equidigital number, since it uses as much as digits as its factorization.

21242511361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29961938.

The product of its digits is 2880, while the sum is 28.

The spelling of 21242511361 in words is "twenty-one billion, two hundred forty-two million, five hundred eleven thousand, three hundred sixty-one".