1321531 has 4 divisors (see below), whose sum is σ = 1323864. Its totient is φ = 1319200.

The previous prime is 1321517. The next prime is 1321549. The reversal of 1321531 is 1351231.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1321531 - 2¹³ = 1313339 is a prime.

It is a super-2 number, since 2×1321531² = 3492888367922, which contains 22 as substring.

It is a Duffinian number.

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, 291 + ... + 1651.

It is an arithmetic number, because the mean of its divisors is an integer number (330966).

2^1321531 is an apocalyptic number.

1321531 is a deficient number, since it is larger than the sum of its proper divisors (2333).

1321531 is an equidigital number, since it uses as much as digits as its factorization.

1321531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2332.

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

The square root of 1321531 is about 1149.5786184511. The cubic root of 1321531 is about 109.7385249598.

Adding to 1321531 its reverse (1351231), we get a palindrome (2672762).

The spelling of 1321531 in words is "one million, three hundred twenty-one thousand, five hundred thirty-one".