1216331129 has 4 divisors (see below), whose sum is σ = 1309895076. Its totient is φ = 1122767184.

The previous prime is 1216331117. The next prime is 1216331177. The reversal of 1216331129 is 9211336121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9211336121 = 13 ⋅708564317.

It can be written as a sum of positive squares in 2 ways, for example, as 70644025 + 1145687104 = 8405^2 + 33848^2 .

It is a cyclic number.

It is not a de Polignac number, because 1216331129 - 2²⁴ = 1199553913 is a prime.

It is a super-2 number, since 2×1216331129² = 2958922830748829282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1216331029) 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, 46781954 + ... + 46781979.

It is an arithmetic number, because the mean of its divisors is an integer number (327473769).

Almost surely, 2^1216331129 is an apocalyptic number.

It is an amenable number.

1216331129 is a deficient number, since it is larger than the sum of its proper divisors (93563947).

1216331129 is an equidigital number, since it uses as much as digits as its factorization.

1216331129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93563946.

The product of its digits is 1944, while the sum is 29.

The square root of 1216331129 is about 34875.9391128038. The cubic root of 1216331129 is about 1067.4575350347.

The spelling of 1216331129 in words is "one billion, two hundred sixteen million, three hundred thirty-one thousand, one hundred twenty-nine".