1331521 has 2 divisors, whose sum is σ = 1331522. Its totient is φ = 1331520.

The previous prime is 1331513. The next prime is 1331527. The reversal of 1331521 is 1251331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1199025 + 132496 = 1095^2 + 364^2 .

It is a cyclic number.

It is not a de Polignac number, because 1331521 - 2³ = 1331513 is a prime.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 1331495 and 1331504.

It is not a weakly prime, because it can be changed into another prime (1331527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665760 + 665761.

It is an arithmetic number, because the mean of its divisors is an integer number (665761).

2^1331521 is an apocalyptic number.

It is an amenable number.

1331521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331521 is an equidigital number, since it uses as much as digits as its factorization.

1331521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90, while the sum is 16.

The square root of 1331521 is about 1153.9155081721. The cubic root of 1331521 is about 110.0143507448.

Adding to 1331521 its reverse (1251331), we get a palindrome (2582852).

The spelling of 1331521 in words is "one million, three hundred thirty-one thousand, five hundred twenty-one".