1331021 has 4 divisors (see below), whose sum is σ = 1333344. Its totient is φ = 1328700.

The previous prime is 1330997. The next prime is 1331023. The reversal of 1331021 is 1201331.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1201331 = 523 ⋅2297.

It is a cyclic number.

It is not a de Polignac number, because 1331021 - 2⁶ = 1330957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1330993 and 1331011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 386 + ... + 1676.

It is an arithmetic number, because the mean of its divisors is an integer number (333336).

2^1331021 is an apocalyptic number.

It is an amenable number.

1331021 is a deficient number, since it is larger than the sum of its proper divisors (2323).

1331021 is a wasteful number, since it uses less digits than its factorization.

1331021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2322.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 1331021 is about 1153.6988341851. The cubic root of 1331021 is about 110.0005785094. Note that the first 3 decimals are identical.

Adding to 1331021 its reverse (1201331), we get a palindrome (2532352).

It can be divided in two parts, 13310 and 21, that added together give a palindrome (13331).

The spelling of 1331021 in words is "one million, three hundred thirty-one thousand, twenty-one".