21121011221201 has 8 divisors (see below), whose sum is σ = 21257161991784. Its totient is φ = 20984880983040.

The previous prime is 21121011221171. The next prime is 21121011221257. The reversal of 21121011221201 is 10212211012112.

It can be written as a sum of positive squares in 4 ways, for example, as 1576654411201 + 19544356810000 = 1255649^2 + 4420900^2 .

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 21121011221201 - 2¹⁸ = 21121010959057 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21121011221201.

It is not an unprimeable number, because it can be changed into a prime (21121011220201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3066470 + ... + 7186463.

It is an arithmetic number, because the mean of its divisors is an integer number (2657145248973).

Almost surely, 2^{21121011221201} is an apocalyptic number.

It is an amenable number.

21121011221201 is a deficient number, since it is larger than the sum of its proper divisors (136150770583).

21121011221201 is a wasteful number, since it uses less digits than its factorization.

21121011221201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10266211.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21121011221201 its reverse (10212211012112), we get a palindrome (31333222233313).

The spelling of 21121011221201 in words is "twenty-one trillion, one hundred twenty-one billion, eleven million, two hundred twenty-one thousand, two hundred one".