21123301121 has 4 divisors (see below), whose sum is σ = 22748170452. Its totient is φ = 19498431792.

The previous prime is 21123301099. The next prime is 21123301169. The reversal of 21123301121 is 12110332112.

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 3036010000 + 18087291121 = 55100^2 + 134489^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21123301121 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 21123301121.

It is not an unprimeable number, because it can be changed into a prime (21123301181) 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, 812434646 + ... + 812434671.

It is an arithmetic number, because the mean of its divisors is an integer number (5687042613).

Almost surely, 2^21123301121 is an apocalyptic number.

It is an amenable number.

21123301121 is a deficient number, since it is larger than the sum of its proper divisors (1624869331).

21123301121 is a wasteful number, since it uses less digits than its factorization.

21123301121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1624869330.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21123301121 its reverse (12110332112), we get a palindrome (33233633233).

The spelling of 21123301121 in words is "twenty-one billion, one hundred twenty-three million, three hundred one thousand, one hundred twenty-one".