21012221201 has 16 divisors (see below), whose sum is σ = 22795449600. Its totient is φ = 19303392528.

The previous prime is 21012221183. The next prime is 21012221207. The reversal of 21012221201 is 10212221012.

It is a cyclic number.

It is not a de Polignac number, because 21012221201 - 2¹⁸ = 21011959057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21012221207) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21050 + ... + 206076.

It is an arithmetic number, because the mean of its divisors is an integer number (1424715600).

Almost surely, 2^21012221201 is an apocalyptic number.

It is an amenable number.

21012221201 is a deficient number, since it is larger than the sum of its proper divisors (1783228399).

21012221201 is a wasteful number, since it uses less digits than its factorization.

21012221201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185228.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21012221201 its reverse (10212221012), we get a palindrome (31224442213).

The spelling of 21012221201 in words is "twenty-one billion, twelve million, two hundred twenty-one thousand, two hundred one".