1261336321 has 16 divisors (see below), whose sum is σ = 1473970176. Its totient is φ = 1056869136.

The previous prime is 1261336319. The next prime is 1261336387. The reversal of 1261336321 is 1236331621.

It is a cyclic number.

It is not a de Polignac number, because 1261336321 - 2¹ = 1261336319 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1261336321.

It is not an unprimeable number, because it can be changed into a prime (1261336421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 355860 + ... + 359386.

It is an arithmetic number, because the mean of its divisors is an integer number (92123136).

Almost surely, 2^1261336321 is an apocalyptic number.

It is an amenable number.

1261336321 is a deficient number, since it is larger than the sum of its proper divisors (212633855).

1261336321 is a wasteful number, since it uses less digits than its factorization.

1261336321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4668.

The product of its digits is 3888, while the sum is 28.

The square root of 1261336321 is about 35515.2970000252. The cubic root of 1261336321 is about 1080.4639984413.

Adding to 1261336321 its reverse (1236331621), we get a palindrome (2497667942).

The spelling of 1261336321 in words is "one billion, two hundred sixty-one million, three hundred thirty-six thousand, three hundred twenty-one".