1321351261 has 4 divisors (see below), whose sum is σ = 1329263712. Its totient is φ = 1313438812.

The previous prime is 1321351253. The next prime is 1321351309. The reversal of 1321351261 is 1621531231.

It is a happy number.

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 1321351261 - 2³ = 1321351253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321351201) 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, 3955975 + ... + 3956308.

It is an arithmetic number, because the mean of its divisors is an integer number (332315928).

Almost surely, 2^1321351261 is an apocalyptic number.

It is an amenable number.

1321351261 is a deficient number, since it is larger than the sum of its proper divisors (7912451).

1321351261 is an equidigital number, since it uses as much as digits as its factorization.

1321351261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7912450.

The product of its digits is 1080, while the sum is 25.

The square root of 1321351261 is about 36350.3956099518. The cubic root of 1321351261 is about 1097.3354962264.

Adding to 1321351261 its reverse (1621531231), we get a palindrome (2942882492).

The spelling of 1321351261 in words is "one billion, three hundred twenty-one million, three hundred fifty-one thousand, two hundred sixty-one".