1221404121 has 48 divisors (see below), whose sum is σ = 2152989696. Its totient is φ = 652040928.

The previous prime is 1221404111. The next prime is 1221404131. The reversal of 1221404121 is 1214041221.

It is an interprime number because it is at equal distance from previous prime (1221404111) and next prime (1221404131).

It is not a de Polignac number, because 1221404121 - 2⁵ = 1221404089 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221404094 and 1221404103.

It is not an unprimeable number, because it can be changed into a prime (1221404101) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 52506 + ... + 72108.

It is an arithmetic number, because the mean of its divisors is an integer number (44853952).

Almost surely, 2^1221404121 is an apocalyptic number.

It is an amenable number.

1221404121 is a deficient number, since it is larger than the sum of its proper divisors (931585575).

1221404121 is a wasteful number, since it uses less digits than its factorization.

1221404121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19682 (or 19679 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 1221404121 is about 34948.5925467679. The cubic root of 1221404121 is about 1068.9395033208.

Adding to 1221404121 its reverse (1214041221), we get a palindrome (2435445342).

It can be divided in two parts, 1 and 221404121, that added together give a palindrome (221404122).

The spelling of 1221404121 in words is "one billion, two hundred twenty-one million, four hundred four thousand, one hundred twenty-one".