1321521 has 4 divisors (see below), whose sum is σ = 1762032. Its totient is φ = 881012.

The previous prime is 1321517. The next prime is 1321549. The reversal of 1321521 is 1251231.

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.

It is a cyclic number.

It is not a de Polignac number, because 1321521 - 2² = 1321517 is a prime.

It is a D-number.

1321521 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1321521.

It is not an unprimeable number, because it can be changed into a prime (1321571) 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, 220251 + ... + 220256.

It is an arithmetic number, because the mean of its divisors is an integer number (440508).

2^1321521 is an apocalyptic number.

It is an amenable number.

1321521 is a deficient number, since it is larger than the sum of its proper divisors (440511).

1321521 is an equidigital number, since it uses as much as digits as its factorization.

1321521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440510.

The product of its digits is 60, while the sum is 15.

The square root of 1321521 is about 1149.5742690231. The cubic root of 1321521 is about 109.7382481627.

Adding to 1321521 its reverse (1251231), we get a palindrome (2572752).

It can be divided in two parts, 132 and 1521, that added together give a triangular number (1653 = T₅₇).

The spelling of 1321521 in words is "one million, three hundred twenty-one thousand, five hundred twenty-one".