21122102200021 has 4 divisors (see below), whose sum is σ = 21122222278444. Its totient is φ = 21121982121600.

The previous prime is 21122102200019. The next prime is 21122102200049. The reversal of 21122102200021 is 12000220122112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5718722218225 + 15403379981796 = 2391385^2 + 3924714^2 .

It is a cyclic number.

It is not a de Polignac number, because 21122102200021 - 2¹ = 21122102200019 is a prime.

It is a super-2 number, since 2×21122102200021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21122102199968 and 21122102200004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122102201021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59774970 + ... + 60127291.

It is an arithmetic number, because the mean of its divisors is an integer number (5280555569611).

Almost surely, 2^{21122102200021} is an apocalyptic number.

It is an amenable number.

21122102200021 is a deficient number, since it is larger than the sum of its proper divisors (120078423).

21122102200021 is a wasteful number, since it uses less digits than its factorization.

21122102200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120078422.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21122102200021 its reverse (12000220122112), we get a palindrome (33122322322133).

The spelling of 21122102200021 in words is "twenty-one trillion, one hundred twenty-two billion, one hundred two million, two hundred thousand, twenty-one".