1221038401221 has 24 divisors (see below), whose sum is σ = 1782203134296. Its totient is φ = 805505126400.

The previous prime is 1221038401207. The next prime is 1221038401223. The reversal of 1221038401221 is 1221048301221.

It is a happy number.

1221038401221 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 0 + 38 + 401 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 174294560196 + 1046743841025 = 417486^2 + 1023105^2 .

It is not a de Polignac number, because 1221038401221 - 2⁵ = 1221038401189 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221038401223) 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, 1210341 + ... + 1976613.

It is an arithmetic number, because the mean of its divisors is an integer number (74258463929).

Almost surely, 2^{1221038401221} is an apocalyptic number.

It is an amenable number.

1221038401221 is a deficient number, since it is larger than the sum of its proper divisors (561164733075).

1221038401221 is a wasteful number, since it uses less digits than its factorization.

1221038401221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 768133 (or 768130 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The spelling of 1221038401221 in words is "one trillion, two hundred twenty-one billion, thirty-eight million, four hundred one thousand, two hundred twenty-one".