21212220200121 has 24 divisors (see below), whose sum is σ = 31013189188800. Its totient is φ = 13970215476000.

The previous prime is 21212220200107. The next prime is 21212220200131. The reversal of 21212220200121 is 12100202221212.

It is a happy number.

21212220200121 is a `hidden beast` number, since 2 + 121 + 2 + 220 + 200 + 121 = 666.

It is not a de Polignac number, because 21212220200121 - 2⁷ = 21212220199993 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21212220200094 and 21212220200103.

It is not an unprimeable number, because it can be changed into a prime (21212220200131) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42871971 + ... + 43363928.

It is an arithmetic number, because the mean of its divisors is an integer number (1292216216200).

Almost surely, 2^{21212220200121} is an apocalyptic number.

It is an amenable number.

21212220200121 is a deficient number, since it is larger than the sum of its proper divisors (9800968988679).

21212220200121 is a wasteful number, since it uses less digits than its factorization.

21212220200121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86236237 (or 86236234 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21212220200121 its reverse (12100202221212), we get a palindrome (33312422421333).

The spelling of 21212220200121 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty million, two hundred thousand, one hundred twenty-one".