1211221210101 has 16 divisors (see below), whose sum is σ = 1845778940544. Its totient is φ = 692085708864.

The previous prime is 1211221210091. The next prime is 1211221210159. The reversal of 1211221210101 is 1010121221121.

It is a happy number.

It is not a de Polignac number, because 1211221210101 - 2⁹ = 1211221209589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211221210201) 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, 1328206 + ... + 2046111.

It is an arithmetic number, because the mean of its divisors is an integer number (115361183784).

Almost surely, 2^{1211221210101} is an apocalyptic number.

It is an amenable number.

1211221210101 is a deficient number, since it is larger than the sum of its proper divisors (634557730443).

1211221210101 is a wasteful number, since it uses less digits than its factorization.

1211221210101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3391420.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1211221210101 its reverse (1010121221121), we get a palindrome (2221342431222).

The spelling of 1211221210101 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred ten thousand, one hundred one".