1221203121 has 8 divisors (see below), whose sum is σ = 1628486304. Its totient is φ = 814027680.

The previous prime is 1221203117. The next prime is 1221203129. The reversal of 1221203121 is 1213021221.

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

It is not a de Polignac number, because 1221203121 - 2² = 1221203117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1221203121.

It is not an unprimeable number, because it can be changed into a prime (1221203129) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4885 + ... + 49661.

It is an arithmetic number, because the mean of its divisors is an integer number (203560788).

Almost surely, 2^1221203121 is an apocalyptic number.

It is an amenable number.

1221203121 is a deficient number, since it is larger than the sum of its proper divisors (407283183).

1221203121 is an equidigital number, since it uses as much as digits as its factorization.

1221203121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53871.

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1221203121 is about 34945.7167761659. The cubic root of 1221203121 is about 1068.8808635352.

Adding to 1221203121 its reverse (1213021221), we get a palindrome (2434224342).

The spelling of 1221203121 in words is "one billion, two hundred twenty-one million, two hundred three thousand, one hundred twenty-one".