21002212321 has 16 divisors (see below), whose sum is σ = 22060373328. Its totient is φ = 19974988800.

The previous prime is 21002212313. The next prime is 21002212327. The reversal of 21002212321 is 12321220012.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 85821696 + 20916390625 = 9264^2 + 144625^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002212321 - 2³ = 21002212313 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21002212295 and 21002212304.

It is not an unprimeable number, because it can be changed into a prime (21002212327) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 310381 + ... + 371941.

It is an arithmetic number, because the mean of its divisors is an integer number (1378773333).

Almost surely, 2^21002212321 is an apocalyptic number.

It is an amenable number.

21002212321 is a deficient number, since it is larger than the sum of its proper divisors (1058161007).

21002212321 is a wasteful number, since it uses less digits than its factorization.

21002212321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61812.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21002212321 its reverse (12321220012), we get a palindrome (33323432333).

The spelling of 21002212321 in words is "twenty-one billion, two million, two hundred twelve thousand, three hundred twenty-one".