21102111421 has 8 divisors (see below), whose sum is σ = 21248154104. Its totient is φ = 20956216320.

The previous prime is 21102111403. The next prime is 21102111517. The reversal of 21102111421 is 12411120112.

It can be written as a sum of positive squares in 4 ways, for example, as 179935396 + 20922176025 = 13414^2 + 144645^2 .

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 21102111421 - 2¹⁵ = 21102078653 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21102111395 and 21102111404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102511421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 258181 + ... + 329941.

It is an arithmetic number, because the mean of its divisors is an integer number (2656019263).

Almost surely, 2^21102111421 is an apocalyptic number.

It is an amenable number.

21102111421 is a deficient number, since it is larger than the sum of its proper divisors (146042683).

21102111421 is a wasteful number, since it uses less digits than its factorization.

21102111421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73791.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21102111421 its reverse (12411120112), we get a palindrome (33513231533).

The spelling of 21102111421 in words is "twenty-one billion, one hundred two million, one hundred eleven thousand, four hundred twenty-one".