1212220121 has 16 divisors (see below), whose sum is σ = 1482226560. Its totient is φ = 968215680.

The previous prime is 1212220117. The next prime is 1212220123. The reversal of 1212220121 is 1210222121.

It is not a de Polignac number, because 1212220121 - 2² = 1212220117 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1212220096 and 1212220105.

It is not an unprimeable number, because it can be changed into a prime (1212220123) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66596 + ... + 82821.

It is an arithmetic number, because the mean of its divisors is an integer number (92639160).

Almost surely, 2^1212220121 is an apocalyptic number.

It is an amenable number.

1212220121 is a deficient number, since it is larger than the sum of its proper divisors (270006439).

1212220121 is a wasteful number, since it uses less digits than its factorization.

1212220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149504.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 1212220121 is about 34816.9516327895. The cubic root of 1212220121 is about 1066.2535647186.

Adding to 1212220121 its reverse (1210222121), we get a palindrome (2422442242).

The spelling of 1212220121 in words is "one billion, two hundred twelve million, two hundred twenty thousand, one hundred twenty-one".