21320311121 has 4 divisors (see below), whose sum is σ = 21330548592. Its totient is φ = 21310073652.

The previous prime is 21320311093. The next prime is 21320311123. The reversal of 21320311121 is 12111302312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21320311121 - 2²² = 21316116817 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 21320311121.

It is not an unprimeable number, because it can be changed into a prime (21320311123) 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, 5115611 + ... + 5119776.

It is an arithmetic number, because the mean of its divisors is an integer number (5332637148).

Almost surely, 2^21320311121 is an apocalyptic number.

It is an amenable number.

21320311121 is a deficient number, since it is larger than the sum of its proper divisors (10237471).

21320311121 is a wasteful number, since it uses less digits than its factorization.

21320311121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10237470.

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

Adding to 21320311121 its reverse (12111302312), we get a palindrome (33431613433).

The spelling of 21320311121 in words is "twenty-one billion, three hundred twenty million, three hundred eleven thousand, one hundred twenty-one".