21210311321 has 8 divisors (see below), whose sum is σ = 22004544000. Its totient is φ = 20422955520.

The previous prime is 21210311303. The next prime is 21210311357. The reversal of 21210311321 is 12311301212.

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-21210311321 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210311321.

It is not an unprimeable number, because it can be changed into a prime (21210311371) 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, 1712936 + ... + 1725273.

It is an arithmetic number, because the mean of its divisors is an integer number (2750568000).

Almost surely, 2^21210311321 is an apocalyptic number.

It is an amenable number.

21210311321 is a deficient number, since it is larger than the sum of its proper divisors (794232679).

21210311321 is a wasteful number, since it uses less digits than its factorization.

21210311321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3438439.

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

Adding to 21210311321 its reverse (12311301212), we get a palindrome (33521612533).

The spelling of 21210311321 in words is "twenty-one billion, two hundred ten million, three hundred eleven thousand, three hundred twenty-one".