21213022121 has 8 divisors (see below), whose sum is σ = 21575349000. Its totient is φ = 20851165440.

The previous prime is 21213022097. The next prime is 21213022123. The reversal of 21213022121 is 12122031212.

It can be written as a sum of positive squares in 4 ways, for example, as 1388382121 + 19824640000 = 37261^2 + 140800^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213022121 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 21213022121.

It is not an unprimeable number, because it can be changed into a prime (21213022123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25946 + ... + 207603.

It is an arithmetic number, because the mean of its divisors is an integer number (2696918625).

Almost surely, 2^21213022121 is an apocalyptic number.

It is an amenable number.

21213022121 is a deficient number, since it is larger than the sum of its proper divisors (362326879).

21213022121 is a wasteful number, since it uses less digits than its factorization.

21213022121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235099.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21213022121 its reverse (12122031212), we get a palindrome (33335053333).

Subtracting from 21213022121 its reverse (12122031212), we obtain a palindrome (9090990909).

The spelling of 21213022121 in words is "twenty-one billion, two hundred thirteen million, twenty-two thousand, one hundred twenty-one".