1331621 has 4 divisors (see below), whose sum is σ = 1338144. Its totient is φ = 1325100.

The previous prime is 1331611. The next prime is 1331633. The reversal of 1331621 is 1261331.

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 an emirpimes, since its reverse is a distinct semiprime: 1261331 = 283 ⋅4457.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1331621 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1331621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331611) 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, 2945 + ... + 3366.

It is an arithmetic number, because the mean of its divisors is an integer number (334536).

2^1331621 is an apocalyptic number.

It is an amenable number.

1331621 is a deficient number, since it is larger than the sum of its proper divisors (6523).

1331621 is an equidigital number, since it uses as much as digits as its factorization.

1331621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6522.

The product of its digits is 108, while the sum is 17.

The square root of 1331621 is about 1153.9588380874. The cubic root of 1331621 is about 110.0171047781.

Adding to 1331621 its reverse (1261331), we get a palindrome (2592952).

The spelling of 1331621 in words is "one million, three hundred thirty-one thousand, six hundred twenty-one".