1221203311 has 8 divisors (see below), whose sum is σ = 1292694480. Its totient is φ = 1151670912.

The previous prime is 1221203309. The next prime is 1221203351. The reversal of 1221203311 is 1133021221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221203311 - 2¹ = 1221203309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221203351) 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, 488410 + ... + 490903.

It is an arithmetic number, because the mean of its divisors is an integer number (161586810).

Almost surely, 2^1221203311 is an apocalyptic number.

1221203311 is a deficient number, since it is larger than the sum of its proper divisors (71491169).

1221203311 is an equidigital number, since it uses as much as digits as its factorization.

1221203311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 979385.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1221203311 is about 34945.7194946677. The cubic root of 1221203311 is about 1068.8809189689.

Adding to 1221203311 its reverse (1133021221), we get a palindrome (2354224532).

The spelling of 1221203311 in words is "one billion, two hundred twenty-one million, two hundred three thousand, three hundred eleven".