1221312011 has 8 divisors (see below), whose sum is σ = 1300631904. Its totient is φ = 1142823040.

The previous prime is 1221312007. The next prime is 1221312013. The reversal of 1221312011 is 1102131221.

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 1221312011 - 2² = 1221312007 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221312013) 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, 204695 + ... + 210576.

It is an arithmetic number, because the mean of its divisors is an integer number (162578988).

Almost surely, 2^1221312011 is an apocalyptic number.

1221312011 is a deficient number, since it is larger than the sum of its proper divisors (79319893).

1221312011 is a wasteful number, since it uses less digits than its factorization.

1221312011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415461.

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 1221312011 is about 34947.2747292260. The cubic root of 1221312011 is about 1068.9126319271.

Adding to 1221312011 its reverse (1102131221), we get a palindrome (2323443232).

The spelling of 1221312011 in words is "one billion, two hundred twenty-one million, three hundred twelve thousand, eleven".