21012102022221 has 48 divisors (see below), whose sum is σ = 31846865756160. Its totient is φ = 13843098981360.

The previous prime is 21012102022201. The next prime is 21012102022237. The reversal of 21012102022221 is 12222020121012.

It is a happy number.

21012102022221 is a `hidden beast` number, since 210 + 1 + 210 + 2 + 0 + 22 + 221 = 666.

It is not a de Polignac number, because 21012102022221 - 2¹⁸ = 21012101760077 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21012102022194 and 21012102022203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012102022201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11112576 + ... + 12865206.

It is an arithmetic number, because the mean of its divisors is an integer number (663476369920).

Almost surely, 2^{21012102022221} is an apocalyptic number.

It is an amenable number.

21012102022221 is a deficient number, since it is larger than the sum of its proper divisors (10834763733939).

21012102022221 is a wasteful number, since it uses less digits than its factorization.

21012102022221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1753228 (or 1753216 counting only the distinct ones).

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

Adding to 21012102022221 its reverse (12222020121012), we get a palindrome (33234122143233).

The spelling of 21012102022221 in words is "twenty-one trillion, twelve billion, one hundred two million, twenty-two thousand, two hundred twenty-one".