1331320221 has 24 divisors (see below), whose sum is σ = 2397530304. Its totient is φ = 691594560.

The previous prime is 1331320171. The next prime is 1331320231. The reversal of 1331320221 is 1220231331.

It is not a de Polignac number, because 1331320221 - 2⁹ = 1331319709 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1331320194 and 1331320203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331320231) 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, 959856 + ... + 961241.

It is an arithmetic number, because the mean of its divisors is an integer number (99897096).

Almost surely, 2^1331320221 is an apocalyptic number.

1331320221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1331320221 is a deficient number, since it is larger than the sum of its proper divisors (1066210083).

1331320221 is a wasteful number, since it uses less digits than its factorization.

1331320221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1921121 (or 1921118 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 1331320221 is about 36487.2610783545. The cubic root of 1331320221 is about 1100.0882080780.

Adding to 1331320221 its reverse (1220231331), we get a palindrome (2551551552).

The spelling of 1331320221 in words is "one billion, three hundred thirty-one million, three hundred twenty thousand, two hundred twenty-one".