1221125217 has 24 divisors (see below), whose sum is σ = 1768219200. Its totient is φ = 749256768.

The previous prime is 1221125203. The next prime is 1221125219. The reversal of 1221125217 is 7125211221.

It is a happy number.

It is not a de Polignac number, because 1221125217 - 2⁴ = 1221125201 is a prime.

It is a super-2 number, since 2×1221125217² = 2982293591186594178, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221125219) 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, 178659 + ... + 185367.

It is an arithmetic number, because the mean of its divisors is an integer number (73675800).

Almost surely, 2^1221125217 is an apocalyptic number.

It is an amenable number.

1221125217 is a deficient number, since it is larger than the sum of its proper divisors (547093983).

1221125217 is a wasteful number, since it uses less digits than its factorization.

1221125217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7097 (or 7084 counting only the distinct ones).

The product of its digits is 560, while the sum is 24.

The square root of 1221125217 is about 34944.6021153482. The cubic root of 1221125217 is about 1068.8581340744.

Adding to 1221125217 its reverse (7125211221), we get a palindrome (8346336438).

The spelling of 1221125217 in words is "one billion, two hundred twenty-one million, one hundred twenty-five thousand, two hundred seventeen".