1261336129 has 4 divisors (see below), whose sum is σ = 1263435460. Its totient is φ = 1259236800.

The previous prime is 1261336127. The next prime is 1261336183. The reversal of 1261336129 is 9216331621.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1192113729 + 69222400 = 34527^2 + 8320^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261336129 - 2¹ = 1261336127 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1261336094 and 1261336103.

It is not an unprimeable number, because it can be changed into a prime (1261336127) 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, 1048764 + ... + 1049965.

It is an arithmetic number, because the mean of its divisors is an integer number (315858865).

Almost surely, 2^1261336129 is an apocalyptic number.

It is an amenable number.

1261336129 is a deficient number, since it is larger than the sum of its proper divisors (2099331).

1261336129 is an equidigital number, since it uses as much as digits as its factorization.

1261336129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2099330.

The product of its digits is 11664, while the sum is 34.

The square root of 1261336129 is about 35515.2942969645. The cubic root of 1261336129 is about 1080.4639436187.

The spelling of 1261336129 in words is "one billion, two hundred sixty-one million, three hundred thirty-six thousand, one hundred twenty-nine".