1221001221 has 32 divisors (see below), whose sum is σ = 1842247296. Its totient is φ = 712800000.

The previous prime is 1221001189. The next prime is 1221001261.

1221001221 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1221001221 - 2⁵ = 1221001189 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1221001197 and 1221001206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221001261) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 118371 + ... + 128271.

It is an arithmetic number, because the mean of its divisors is an integer number (57570228).

Almost surely, 2^1221001221 is an apocalyptic number.

1221001221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221001221 is a deficient number, since it is larger than the sum of its proper divisors (621246075).

1221001221 is a wasteful number, since it uses less digits than its factorization.

1221001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10053.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1221001221 is about 34942.8278907131. The cubic root of 1221001221 is about 1068.8219547054.

It can be divided in two parts, 122100 and 1221, that multiplied together give a square (149084100 = 12210²).

The spelling of 1221001221 in words is "one billion, two hundred twenty-one million, one thousand, two hundred twenty-one".