1231220221 has 8 divisors (see below), whose sum is σ = 1535027904. Its totient is φ = 959392320.

The previous prime is 1231220209. The next prime is 1231220239. The reversal of 1231220221 is 1220221321.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1231220221 - 2¹⁷ = 1231089149 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1231220195 and 1231220204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1231226221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7994860 + ... + 7995013.

It is an arithmetic number, because the mean of its divisors is an integer number (191878488).

Almost surely, 2^1231220221 is an apocalyptic number.

1231220221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1231220221 is a deficient number, since it is larger than the sum of its proper divisors (303807683).

1231220221 is a wasteful number, since it uses less digits than its factorization.

1231220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15989891.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 1231220221 is about 35088.7477832994. The cubic root of 1231220221 is about 1071.7954602171.

Adding to 1231220221 its reverse (1220221321), we get a palindrome (2451441542).

The spelling of 1231220221 in words is "one billion, two hundred thirty-one million, two hundred twenty thousand, two hundred twenty-one".