21121302121 has 8 divisors (see below), whose sum is σ = 21252055104. Its totient is φ = 20990600400.

The previous prime is 21121302113. The next prime is 21121302131. The reversal of 21121302121 is 12120312112.

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 21121302121 - 2³ = 21121302113 is a prime.

It is a super-3 number, since 3×21121302121³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121302095 and 21121302104.

It is not an unprimeable number, because it can be changed into a prime (21121302131) 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, 1120071 + ... + 1138771.

It is an arithmetic number, because the mean of its divisors is an integer number (2656506888).

Almost surely, 2^21121302121 is an apocalyptic number.

It is an amenable number.

21121302121 is a deficient number, since it is larger than the sum of its proper divisors (130752983).

21121302121 is a wasteful number, since it uses less digits than its factorization.

21121302121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25631.

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

Adding to 21121302121 its reverse (12120312112), we get a palindrome (33241614233).

Subtracting from 21121302121 its reverse (12120312112), we obtain a palindrome (9000990009).

The spelling of 21121302121 in words is "twenty-one billion, one hundred twenty-one million, three hundred two thousand, one hundred twenty-one".