1331221011 has 4 divisors (see below), whose sum is σ = 1774961352. Its totient is φ = 887480672.

The previous prime is 1331221007. The next prime is 1331221019. The reversal of 1331221011 is 1101221331.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1331221011 - 2² = 1331221007 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1331221019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221870166 + ... + 221870171.

It is an arithmetic number, because the mean of its divisors is an integer number (443740338).

Almost surely, 2^1331221011 is an apocalyptic number.

1331221011 is a deficient number, since it is larger than the sum of its proper divisors (443740341).

1331221011 is an equidigital number, since it uses as much as digits as its factorization.

1331221011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443740340.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 1331221011 is about 36485.9015374432. The cubic root of 1331221011 is about 1100.0608812034.

Adding to 1331221011 its reverse (1101221331), we get a palindrome (2432442342).

The spelling of 1331221011 in words is "one billion, three hundred thirty-one million, two hundred twenty-one thousand, eleven".