21012121321 has 8 divisors (see below), whose sum is σ = 21051716000. Its totient is φ = 20972552832.

The previous prime is 21012121309. The next prime is 21012121331. The reversal of 21012121321 is 12312121012.

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

It is a cyclic number.

It is not a de Polignac number, because 21012121321 - 2⁵ = 21012121289 is a prime.

It is a super-3 number, since 3×21012121321³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012121295 and 21012121304.

It is not an unprimeable number, because it can be changed into a prime (21012121331) 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, 2350366 + ... + 2359288.

It is an arithmetic number, because the mean of its divisors is an integer number (2631464500).

Almost surely, 2^21012121321 is an apocalyptic number.

It is an amenable number.

21012121321 is a deficient number, since it is larger than the sum of its proper divisors (39594679).

21012121321 is an equidigital number, since it uses as much as digits as its factorization.

21012121321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13095.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21012121321 its reverse (12312121012), we get a palindrome (33324242333).

The spelling of 21012121321 in words is "twenty-one billion, twelve million, one hundred twenty-one thousand, three hundred twenty-one".