1221221212011 has 24 divisors (see below), whose sum is σ = 1918229829984. Its totient is φ = 745546809600.

The previous prime is 1221221212007. The next prime is 1221221212037. The reversal of 1221221212011 is 1102121221221.

1221221212011 is a `hidden beast` number, since 1 + 221 + 221 + 21 + 201 + 1 = 666.

It is not a de Polignac number, because 1221221212011 - 2² = 1221221212007 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221221213011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 107857015 + ... + 107868336.

It is an arithmetic number, because the mean of its divisors is an integer number (79926242916).

Almost surely, 2^{1221221212011} is an apocalyptic number.

1221221212011 is a deficient number, since it is larger than the sum of its proper divisors (697008617973).

1221221212011 is a wasteful number, since it uses less digits than its factorization.

1221221212011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215725411 (or 215725408 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 1221221212011 its reverse (1102121221221), we get a palindrome (2323342433232).

The spelling of 1221221212011 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, eleven".