1221201243 has 24 divisors (see below), whose sum is σ = 1813825728. Its totient is φ = 791171712.

The previous prime is 1221201221. The next prime is 1221201251. The reversal of 1221201243 is 3421021221.

It is a happy number.

1221201243 is a `hidden beast` number, since 1 + 221 + 201 + 243 = 666.

It is not a de Polignac number, because 1221201243 - 2⁵ = 1221201211 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221201253) 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, 363630 + ... + 366972.

It is an arithmetic number, because the mean of its divisors is an integer number (75576072).

Almost surely, 2^1221201243 is an apocalyptic number.

1221201243 is a deficient number, since it is larger than the sum of its proper divisors (592624485).

1221201243 is a wasteful number, since it uses less digits than its factorization.

1221201243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4483 (or 4480 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1221201243 is about 34945.6899059097. The cubic root of 1221201243 is about 1068.8803156167.

Adding to 1221201243 its reverse (3421021221), we get a palindrome (4642222464).

The spelling of 1221201243 in words is "one billion, two hundred twenty-one million, two hundred one thousand, two hundred forty-three".