1213531261 has 8 divisors (see below), whose sum is σ = 1228034304. Its totient is φ = 1199077200.

The previous prime is 1213531259. The next prime is 1213531321. The reversal of 1213531261 is 1621353121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1213531261 - 2¹ = 1213531259 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 (1213537261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38860 + ... + 62746.

It is an arithmetic number, because the mean of its divisors is an integer number (153504288).

Almost surely, 2^1213531261 is an apocalyptic number.

It is an amenable number.

1213531261 is a deficient number, since it is larger than the sum of its proper divisors (14503043).

1213531261 is a wasteful number, since it uses less digits than its factorization.

1213531261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24491.

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

The square root of 1213531261 is about 34835.7755906195. The cubic root of 1213531261 is about 1066.6378469535.

Adding to 1213531261 its reverse (1621353121), we get a palindrome (2834884382).

The spelling of 1213531261 in words is "one billion, two hundred thirteen million, five hundred thirty-one thousand, two hundred sixty-one".