21201220221201 has 20 divisors (see below), whose sum is σ = 31678026977124. Its totient is φ = 14130992332800.

The previous prime is 21201220221191. The next prime is 21201220221221. The reversal of 21201220221201 is 10212202210212.

It is a happy number.

21201220221201 is a `hidden beast` number, since 2 + 1 + 20 + 1 + 220 + 221 + 201 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12671321702400 + 8529898518801 = 3559680^2 + 2920599^2 .

It is not a de Polignac number, because 21201220221201 - 2¹⁴ = 21201220204817 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21201220221221) 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 19 ways as a sum of consecutive naturals, for example, 28842960 + ... + 29568881.

Almost surely, 2^{21201220221201} is an apocalyptic number.

It is an amenable number.

21201220221201 is a deficient number, since it is larger than the sum of its proper divisors (10476806755923).

21201220221201 is an equidigital number, since it uses as much as digits as its factorization.

21201220221201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58416334 (or 58416325 counting only the distinct ones).

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

Adding to 21201220221201 its reverse (10212202210212), we get a palindrome (31413422431413).

The spelling of 21201220221201 in words is "twenty-one trillion, two hundred one billion, two hundred twenty million, two hundred twenty-one thousand, two hundred one".