221221221221012 has 6 divisors (see below), whose sum is σ = 387137137136778. Its totient is φ = 110610610610504.

The previous prime is 221221221221009. The next prime is 221221221221023. The reversal of 221221221221012 is 210122122122122.

It can be written as a sum of positive squares in only one way, i.e., 182099748980356 + 39121472240656 = 13494434^2 + 6254716^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27652652652623 + ... + 27652652652630.

It is an arithmetic number, because the mean of its divisors is an integer number (64522856189463).

Almost surely, 2^{221221221221012} is an apocalyptic number.

It is an amenable number.

221221221221012 is a deficient number, since it is larger than the sum of its proper divisors (165915915915766).

221221221221012 is a wasteful number, since it uses less digits than its factorization.

221221221221012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55305305305257 (or 55305305305255 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 23.

Adding to 221221221221012 its reverse (210122122122122), we get a palindrome (431343343343134).

The spelling of 221221221221012 in words is "two hundred twenty-one trillion, two hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-one thousand, twelve".