1311212129 has 4 divisors (see below), whose sum is σ = 1368221376. Its totient is φ = 1254202884.

The previous prime is 1311212117. The next prime is 1311212137. The reversal of 1311212129 is 9212121131.

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, and also an emirpimes, since its reverse is a distinct semiprime: 9212121131 = 89 ⋅103506979.

It is a cyclic number.

It is not a de Polignac number, because 1311212129 - 2²⁴ = 1294434913 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 57009223 = 1311212129 / (1 + 3 + 1 + 1 + 2 + 1 + 2 + 1 + 2 + 9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1310212129) 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 3 ways as a sum of consecutive naturals, for example, 28504589 + ... + 28504634.

It is an arithmetic number, because the mean of its divisors is an integer number (342055344).

Almost surely, 2^1311212129 is an apocalyptic number.

It is an amenable number.

1311212129 is a deficient number, since it is larger than the sum of its proper divisors (57009247).

1311212129 is an equidigital number, since it uses as much as digits as its factorization.

1311212129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57009246.

The product of its digits is 216, while the sum is 23.

The square root of 1311212129 is about 36210.6631947000. The cubic root of 1311212129 is about 1094.5215563049.

The spelling of 1311212129 in words is "one billion, three hundred eleven million, two hundred twelve thousand, one hundred twenty-nine".