1216313431 has 4 divisors (see below), whose sum is σ = 1220275672. Its totient is φ = 1212351192.

The previous prime is 1216313429. The next prime is 1216313459. The reversal of 1216313431 is 1343136121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1343136121 = 59 ⋅22765019.

It is a cyclic number.

It is not a de Polignac number, because 1216313431 - 2¹ = 1216313429 is a prime.

It is a super-2 number, since 2×1216313431² = 2958836724861983522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1216313396 and 1216313405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1216313411) 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, 1980660 + ... + 1981273.

It is an arithmetic number, because the mean of its divisors is an integer number (305068918).

Almost surely, 2^1216313431 is an apocalyptic number.

1216313431 is a deficient number, since it is larger than the sum of its proper divisors (3962241).

1216313431 is an equidigital number, since it uses as much as digits as its factorization.

1216313431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3962240.

The product of its digits is 1296, while the sum is 25.

The square root of 1216313431 is about 34875.6853839462. The cubic root of 1216313431 is about 1067.4523577288.

Adding to 1216313431 its reverse (1343136121), we get a palindrome (2559449552).

The spelling of 1216313431 in words is "one billion, two hundred sixteen million, three hundred thirteen thousand, four hundred thirty-one".